up lect 17

This commit is contained in:
Andreaierardi 2020-05-17 17:34:38 +02:00
parent c08a027392
commit b833008daa
12 changed files with 706 additions and 30 deletions

View File

@ -0,0 +1,9 @@
\relax
\@nameuse{bbl@beforestart}
\babel@aux{english}{}
\@writefile{toc}{\contentsline {chapter}{\numberline {1}Lecture 17 - 11-05-2020}{1}\protected@file@percent }
\@writefile{lof}{\addvspace {10\p@ }}
\@writefile{lot}{\addvspace {10\p@ }}
\@writefile{toc}{\contentsline {section}{\numberline {1.1}Strongly convex loss functions}{1}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {1.1.1}OGD for Strongly Convex losses}{1}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {1.1.2}Relate sequential risk and statistical risk}{2}\protected@file@percent }

View File

@ -0,0 +1,424 @@
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (MiKTeX 2.9.7300 64-bit) (preloaded format=pdflatex 2020.4.13) 17 MAY 2020 17:33
entering extended mode
**./lecture17.tex
(lecture17.tex
LaTeX2e <2020-02-02> patch level 5
L3 programming layer <2020-03-06>
("C:\Program Files\MiKTeX 2.9\tex/latex/subfiles\subfiles.cls"
Document Class: subfiles 2020/02/14 v1.6 Multi-file projects (class)
Preamble taken from file `../main.tex'
("C:\Program Files\MiKTeX 2.9\tex/latex/tools\verbatim.sty"
Package: verbatim 2019/11/10 v1.5r LaTeX2e package for verbatim enhancements
\every@verbatim=\toks15
\verbatim@line=\toks16
\verbatim@in@stream=\read2
)
("C:\Program Files\MiKTeX 2.9\tex/latex/import\import.sty"
Package: import 2020/04/01 v 6.2
) (../main.tex
("C:\Program Files\MiKTeX 2.9\tex/latex/base\report.cls"
Document Class: report 2019/12/20 v1.4l Standard LaTeX document class
("C:\Program Files\MiKTeX 2.9\tex/latex/base\size12.clo"
File: size12.clo 2019/12/20 v1.4l Standard LaTeX file (size option)
)
\c@part=\count167
\c@chapter=\count168
\c@section=\count169
\c@subsection=\count170
\c@subsubsection=\count171
\c@paragraph=\count172
\c@subparagraph=\count173
\c@figure=\count174
\c@table=\count175
\abovecaptionskip=\skip47
\belowcaptionskip=\skip48
\bibindent=\dimen134
)
("C:\Program Files\MiKTeX 2.9\tex/latex/amsmath\amsmath.sty"
Package: amsmath 2020/01/20 v2.17e AMS math features
\@mathmargin=\skip49
For additional information on amsmath, use the `?' option.
("C:\Program Files\MiKTeX 2.9\tex/latex/amsmath\amstext.sty"
Package: amstext 2000/06/29 v2.01 AMS text
("C:\Program Files\MiKTeX 2.9\tex/latex/amsmath\amsgen.sty"
File: amsgen.sty 1999/11/30 v2.0 generic functions
\@emptytoks=\toks17
\ex@=\dimen135
))
("C:\Program Files\MiKTeX 2.9\tex/latex/amsmath\amsbsy.sty"
Package: amsbsy 1999/11/29 v1.2d Bold Symbols
\pmbraise@=\dimen136
)
("C:\Program Files\MiKTeX 2.9\tex/latex/amsmath\amsopn.sty"
Package: amsopn 2016/03/08 v2.02 operator names
)
\inf@bad=\count176
LaTeX Info: Redefining \frac on input line 227.
\uproot@=\count177
\leftroot@=\count178
LaTeX Info: Redefining \overline on input line 389.
\classnum@=\count179
\DOTSCASE@=\count180
LaTeX Info: Redefining \ldots on input line 486.
LaTeX Info: Redefining \dots on input line 489.
LaTeX Info: Redefining \cdots on input line 610.
\Mathstrutbox@=\box45
\strutbox@=\box46
\big@size=\dimen137
LaTeX Font Info: Redeclaring font encoding OML on input line 733.
LaTeX Font Info: Redeclaring font encoding OMS on input line 734.
\macc@depth=\count181
\c@MaxMatrixCols=\count182
\dotsspace@=\muskip16
\c@parentequation=\count183
\dspbrk@lvl=\count184
\tag@help=\toks18
\row@=\count185
\column@=\count186
\maxfields@=\count187
\andhelp@=\toks19
\eqnshift@=\dimen138
\alignsep@=\dimen139
\tagshift@=\dimen140
\tagwidth@=\dimen141
\totwidth@=\dimen142
\lineht@=\dimen143
\@envbody=\toks20
\multlinegap=\skip50
\multlinetaggap=\skip51
\mathdisplay@stack=\toks21
LaTeX Info: Redefining \[ on input line 2859.
LaTeX Info: Redefining \] on input line 2860.
)
("C:\Program Files\MiKTeX 2.9\tex/latex/systeme\systeme.sty"
("C:\Program Files\MiKTeX 2.9\tex/latex/xstring\xstring.sty"
("C:\Program Files\MiKTeX 2.9\tex/generic/xstring\xstring.tex"
\integerpart=\count188
\decimalpart=\count189
)
Package: xstring 2019/02/06 v1.83 String manipulations (CT)
)
("C:\Program Files\MiKTeX 2.9\tex/generic/systeme\systeme.tex"
\SYS_systemecode=\toks22
\SYS_systempreamble=\toks23
\SYSeqnum=\count190
)
Package: systeme 2019/01/13 v0.32 Mise en forme de systemes d'equations (CT)
)
("C:\Program Files\MiKTeX 2.9\tex/latex/amsfonts\amssymb.sty"
Package: amssymb 2013/01/14 v3.01 AMS font symbols
("C:\Program Files\MiKTeX 2.9\tex/latex/amsfonts\amsfonts.sty"
Package: amsfonts 2013/01/14 v3.01 Basic AMSFonts support
\symAMSa=\mathgroup4
\symAMSb=\mathgroup5
LaTeX Font Info: Redeclaring math symbol \hbar on input line 98.
LaTeX Font Info: Overwriting math alphabet `\mathfrak' in version `bold'
(Font) U/euf/m/n --> U/euf/b/n on input line 106.
))
("C:\Program Files\MiKTeX 2.9\tex/latex/subfiles\subfiles.sty"
Package: subfiles 2020/02/14 v1.6 Multi-file projects (package)
)
("C:\Program Files\MiKTeX 2.9\tex/generic/babel\babel.sty"
Package: babel 2020/02/28 3.41 The Babel package
("C:\Program Files\MiKTeX 2.9\tex/generic/babel\switch.def"
File: switch.def 2020/02/28 3.41 Babel switching mechanism
)
*************************************
* Local config file bblopts.cfg used
*
("C:\Program Files\MiKTeX 2.9\tex/latex/arabi\bblopts.cfg"
File: bblopts.cfg 2005/09/08 v0.1 add Arabic and Farsi to "declared" options of
babel
)
("C:\Program Files\MiKTeX 2.9\tex/latex/babel-english\english.ldf"
Language: english 2017/06/06 v3.3r English support from the babel system
("C:\Program Files\MiKTeX 2.9\tex/generic/babel\babel.def"
File: babel.def 2020/02/28 3.41 Babel common definitions
\babel@savecnt=\count191
\U@D=\dimen144
("C:\Program Files\MiKTeX 2.9\tex/generic/babel\txtbabel.def")
\bbl@readstream=\read3
\bbl@dirlevel=\count192
)
Package babel Info: \l@canadian = using hyphenrules for english
(babel) (\language0) on input line 102.
Package babel Info: \l@australian = using hyphenrules for ukenglish
(babel) (\language72) on input line 105.
Package babel Info: \l@newzealand = using hyphenrules for ukenglish
(babel) (\language72) on input line 108.
))
("C:\Program Files\MiKTeX 2.9\tex/latex/xcolor\xcolor.sty"
Package: xcolor 2016/05/11 v2.12 LaTeX color extensions (UK)
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics-cfg\color.cfg"
File: color.cfg 2016/01/02 v1.6 sample color configuration
)
Package xcolor Info: Driver file: pdftex.def on input line 225.
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics-def\pdftex.def"
File: pdftex.def 2018/01/08 v1.0l Graphics/color driver for pdftex
)
Package xcolor Info: Model `cmy' substituted by `cmy0' on input line 1348.
Package xcolor Info: Model `hsb' substituted by `rgb' on input line 1352.
Package xcolor Info: Model `RGB' extended on input line 1364.
Package xcolor Info: Model `HTML' substituted by `rgb' on input line 1366.
Package xcolor Info: Model `Hsb' substituted by `hsb' on input line 1367.
Package xcolor Info: Model `tHsb' substituted by `hsb' on input line 1368.
Package xcolor Info: Model `HSB' substituted by `hsb' on input line 1369.
Package xcolor Info: Model `Gray' substituted by `gray' on input line 1370.
Package xcolor Info: Model `wave' substituted by `hsb' on input line 1371.
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics\dvipsnam.def"
File: dvipsnam.def 2016/06/17 v3.0m Driver-dependent file (DPC,SPQR)
))
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics\graphicx.sty"
Package: graphicx 2019/11/30 v1.2a Enhanced LaTeX Graphics (DPC,SPQR)
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics\keyval.sty"
Package: keyval 2014/10/28 v1.15 key=value parser (DPC)
\KV@toks@=\toks24
)
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics\graphics.sty"
Package: graphics 2019/11/30 v1.4a Standard LaTeX Graphics (DPC,SPQR)
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics\trig.sty"
Package: trig 2016/01/03 v1.10 sin cos tan (DPC)
)
("C:\Program Files\MiKTeX 2.9\tex/latex/graphics-cfg\graphics.cfg"
File: graphics.cfg 2016/06/04 v1.11 sample graphics configuration
)
Package graphics Info: Driver file: pdftex.def on input line 105.
)
\Gin@req@height=\dimen145
\Gin@req@width=\dimen146
)
("C:\Program Files\MiKTeX 2.9\tex/latex/sectsty\sectsty.sty"
Package: sectsty 2002/02/25 v2.0.2 Commands to change all sectional heading sty
les
LaTeX Warning: Command \underbar has changed.
Check if current package is valid.
LaTeX Warning: Command \underline has changed.
Check if current package is valid.
) ("C:\Program Files\MiKTeX 2.9\tex/latex/framed\framed.sty"
Package: framed 2011/10/22 v 0.96: framed or shaded text with page breaks
\OuterFrameSep=\skip52
\fb@frw=\dimen147
\fb@frh=\dimen148
\FrameRule=\dimen149
\FrameSep=\dimen150
)
("C:\Program Files\MiKTeX 2.9\tex/latex/titlesec\titlesec.sty"
Package: titlesec 2019/10/16 v2.13 Sectioning titles
\ttl@box=\box47
\beforetitleunit=\skip53
\aftertitleunit=\skip54
\ttl@plus=\dimen151
\ttl@minus=\dimen152
\ttl@toksa=\toks25
\titlewidth=\dimen153
\titlewidthlast=\dimen154
\titlewidthfirst=\dimen155
)
("C:\Program Files\MiKTeX 2.9\tex/latex/base\fontenc.sty"
Package: fontenc 2020/02/11 v2.0o Standard LaTeX package
)))
("C:\Program Files\MiKTeX 2.9\tex/latex/l3backend\l3backend-pdfmode.def"
File: l3backend-pdfmode.def 2020-03-12 L3 backend support: PDF mode
\l__kernel_color_stack_int=\count193
\l__pdf_internal_box=\box48
)
(lecture17.aux)
\openout1 = `lecture17.aux'.
LaTeX Font Info: Checking defaults for OML/cmm/m/it on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OMS/cmsy/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OT1/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for T1/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for TS1/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OMX/cmex/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for U/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
("C:\Program Files\MiKTeX 2.9\tex/context/base/mkii\supp-pdf.mkii"
[Loading MPS to PDF converter (version 2006.09.02).]
\scratchcounter=\count194
\scratchdimen=\dimen156
\scratchbox=\box49
\nofMPsegments=\count195
\nofMParguments=\count196
\everyMPshowfont=\toks26
\MPscratchCnt=\count197
\MPscratchDim=\dimen157
\MPnumerator=\count198
\makeMPintoPDFobject=\count199
\everyMPtoPDFconversion=\toks27
) ("C:\Program Files\MiKTeX 2.9\tex/latex/epstopdf-pkg\epstopdf-base.sty"
Package: epstopdf-base 2020-01-24 v2.11 Base part for package epstopdf
("C:\Program Files\MiKTeX 2.9\tex/generic/infwarerr\infwarerr.sty"
Package: infwarerr 2019/12/03 v1.5 Providing info/warning/error messages (HO)
)
("C:\Program Files\MiKTeX 2.9\tex/latex/grfext\grfext.sty"
Package: grfext 2019/12/03 v1.3 Manage graphics extensions (HO)
("C:\Program Files\MiKTeX 2.9\tex/generic/kvdefinekeys\kvdefinekeys.sty"
Package: kvdefinekeys 2019-12-19 v1.6 Define keys (HO)
))
("C:\Program Files\MiKTeX 2.9\tex/latex/kvoptions\kvoptions.sty"
Package: kvoptions 2019/11/29 v3.13 Key value format for package options (HO)
("C:\Program Files\MiKTeX 2.9\tex/generic/ltxcmds\ltxcmds.sty"
Package: ltxcmds 2019/12/15 v1.24 LaTeX kernel commands for general use (HO)
)
("C:\Program Files\MiKTeX 2.9\tex/generic/kvsetkeys\kvsetkeys.sty"
Package: kvsetkeys 2019/12/15 v1.18 Key value parser (HO)
))
("C:\Program Files\MiKTeX 2.9\tex/latex/pdftexcmds\pdftexcmds.sty"
Package: pdftexcmds 2019/11/24 v0.31 Utility functions of pdfTeX for LuaTeX (HO
)
("C:\Program Files\MiKTeX 2.9\tex/generic/iftex\iftex.sty"
Package: iftex 2020/03/06 v1.0d TeX engine tests
)
Package pdftexcmds Info: \pdf@primitive is available.
Package pdftexcmds Info: \pdf@ifprimitive is available.
Package pdftexcmds Info: \pdfdraftmode found.
)
Package epstopdf-base Info: Redefining graphics rule for `.eps' on input line 4
85.
Package grfext Info: Graphics extension search list:
(grfext) [.pdf,.png,.jpg,.mps,.jpeg,.jbig2,.jb2,.PDF,.PNG,.JPG,.JPE
G,.JBIG2,.JB2,.eps]
(grfext) \AppendGraphicsExtensions on input line 504.
)
Chapter 1.
LaTeX Font Info: Trying to load font information for U+msa on input line 11.
("C:\Program Files\MiKTeX 2.9\tex/latex/amsfonts\umsa.fd"
File: umsa.fd 2013/01/14 v3.01 AMS symbols A
)
LaTeX Font Info: Trying to load font information for U+msb on input line 11.
("C:\Program Files\MiKTeX 2.9\tex/latex/amsfonts\umsb.fd"
File: umsb.fd 2013/01/14 v3.01 AMS symbols B
)
Underfull \hbox (badness 10000) in paragraph at lines 7--12
[]
Underfull \hbox (badness 10000) in paragraph at lines 12--14
[]
Underfull \hbox (badness 10000) in paragraph at lines 16--21
[]
Overfull \hbox (17.19559pt too wide) detected at line 41
\OT1/cmr/m/n/12 +[][] + [][] + [] [] \OML/cmm/m/it/12 []
[]
[1
{C:/Users/AndreDany/AppData/Local/MiKTeX/2.9/pdftex/config/pdftex.map}]
Overfull \hbox (62.05049pt too wide) detected at line 59
[] [] [] \OML/cmm/m/it/12 << [] []max[]\OMS/cmsy/m/n/12 kr\OML/cmm/m/it/12 `[
]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12 )\OMS/cmsy/m/n/12 k []
[]
Underfull \hbox (badness 10000) in paragraph at lines 59--68
[]
Underfull \hbox (badness 10000) in paragraph at lines 59--68
[]
Underfull \hbox (badness 10000) in paragraph at lines 69--76
[]
Underfull \hbox (badness 10000) in paragraph at lines 78--87
[]
[2]
Underfull \hbox (badness 10000) in paragraph at lines 108--111
[]
Overfull \hbox (2.33182pt too wide) detected at line 113
\OML/cmm/m/it/12 `[]\OT1/cmr/m/n/12 ([]) \OMS/cmsy/m/n/12  [] [] \OML/cmm/m/it
/12 `[]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12 ) [](\OML/cmm/m/it/
12 x[]; y[]\OT1/cmr/m/n/12 )\OML/cmm/m/it/12 :::\OT1/cmr/m/n/12 (\OML/cmm/m/it/
12 x[]; y[]\OT1/cmr/m/n/12 )
[]
Overfull \hbox (24.90033pt too wide) detected at line 136
[] [] \OML/cmm/m/it/12 `[]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12
) \OMS/cmsy/m/n/12  [][] \OT1/cmr/m/n/12 + [] []
[]
[3]
Underfull \hbox (badness 10000) in paragraph at lines 143--146
[]
[4] (lecture17.aux) )
Here is how much of TeX's memory you used:
5106 strings out of 480934
68844 string characters out of 2909670
337085 words of memory out of 3000000
20857 multiletter control sequences out of 15000+200000
548174 words of font info for 59 fonts, out of 3000000 for 9000
1141 hyphenation exceptions out of 8191
42i,8n,50p,333b,142s stack positions out of 5000i,500n,10000p,200000b,50000s
<C:\Users\AndreDany\AppData\Local\MiKTeX\2.9\fonts/pk/ljf
our/jknappen/ec/dpi600\ecti1200.pk> <C:\Users\AndreDany\AppData\Local\MiKTeX\2.
9\fonts/pk/ljfour/jknappen/ec/dpi600\ecbx1200.pk> <C:\Users\AndreDany\AppData\L
ocal\MiKTeX\2.9\fonts/pk/ljfour/jknappen/ec/dpi600\ecbx1440.pk> <C:\Users\Andre
Dany\AppData\Local\MiKTeX\2.9\fonts/pk/ljfour/jknappen/ec/dpi600\ecrm1200.pk> <
C:\Users\AndreDany\AppData\Local\MiKTeX\2.9\fonts/pk/ljfour/jknappen/ec/dpi600\
ecbx1728.pk> <C:\Users\AndreDany\AppData\Local\MiKTeX\2.9\fonts/pk/ljfour/jknap
pen/ec/dpi600\ecbx2488.pk><C:/Program Files/MiKTeX 2.9/fonts/type1/public/amsfo
nts/cm/cmex10.pfb><C:/Program Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/c
mmi12.pfb><C:/Program Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmmi8.pfb
><C:/Program Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmr12.pfb><C:/Prog
ram Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmr8.pfb><C:/Program Files/
MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmsy10.pfb><C:/Program Files/MiKTeX 2
.9/fonts/type1/public/amsfonts/cm/cmsy8.pfb><C:/Program Files/MiKTeX 2.9/fonts/
type1/public/amsfonts/symbols/msbm10.pfb>
Output written on lecture17.pdf (4 pages, 150408 bytes).
PDF statistics:
228 PDF objects out of 1000 (max. 8388607)
0 named destinations out of 1000 (max. 500000)
1 words of extra memory for PDF output out of 10000 (max. 10000000)

View File

@ -3,5 +3,172 @@
\chapter{Lecture 17 - 11-05-2020}
\section{Strongly convex loss functions}
We will saw with OGD but we will see Support Vector Machine(SVM). Very popular learning model.
\\
We will see SVM next to see the part of linear predictor and also speak about Kernel function used with linear predictor to obtain non -linear classifier from a linear classifier.
\\\\
$\ell$ is $\sigma$-SC if $ \quad \forall u,w$:
$$\ell(w) -\ell(u) \leq \nabla \ell(w)^T \, (w-u)- \frac{\sigma}{2} |\ w -u \|^2$$
\\
\subsection{OGD for Strongly Convex losses}
Init: $w_1 =(0,...,0)$\\
For $t = 1,2...$\\
$\qquad w_{t+1} = w_t -\frac{1}{\sigma \, t} \nabla \ell_t(w_t)$ \qquad $\eta_t = \frac{1}{\eta \, t}$
\\
(no projection steps)\\
$$
\ell_t (w_t) - \ell_t(u) \leq \nabla \ell_t (w_t)^T \, (w-u) - \frac{\sigma}{2} \| w_t - u \|^2 \ =
$$
$$
= \ - \frac{1}{\eta_t} (w_{t+1} - w_t)^T \, (w_t-u) - \frac{\sigma}{2} \| w_t -u \|^2 \ =
$$
$$
= \frac{1}{\eta_t} \left( \frac{1}{2} \| w_t - u\|^2 - \frac{1}{2} \| w_{t+1} - u \|^2 + \frac{1}{2} \| w_{t+1} - w_t \|^2 \right) - \frac{\sigma}{2} \| w_t -u \|^2
$$
$$
R_T(u) \ \leq \ \frac{1}{2 \, \eta_1} \|w_1 -u \|^2
\red{- \frac{1}{2 \, \eta_{T+1} } \| w_{T+1} - u \|^2}
- \frac{\sigma
}{2} \| w_1 -u \|^2 +
$$
$$
+ \blue{ $\frac{1}{2} \sum_{t=1}^{T-1} \| w_{t+1} - u \|^2 \left( \frac{1}{\eta_{t+1}} - \frac{1}{\eta_t} - \sigma \right) $} +
\red{\frac{1}{2} \| w_{T+1} - u \|^2 \left( \frac{1}{\eta_{T+1}}
- \frac{1}{\eta_T} \right) }
+ \frac{G^2}{2} \sum_{t=1}^T \eta_t
$$
where red terms cancel out, \blue{blue} (sum) instead is $0$ since $ \sigma(t+1) - \sigma \, t - \sigma$
$$
G = \max_t \| \nabla \ell_t(w_t) \|
$$
$$
R_T(U) \leq \frac{1}{2} \left( \sigma - \sigma \right) \| w_1 -u \|^2 + \frac{G^2}{2} \sum_{t=1}^T \frac{1}{\sigma \, t} \ = \
$$
$$
R_T(U) \leq \frac{G^2}{2} \sum_{t=1}^T \frac{1}{\sigma \, t} \
$$
We know that $\sum_{t=1}^T \frac{1}{T} \leq \ln \left( T+1 \right)$
so:
$$
R_T(U) \ \leq \ \frac{G^2}{2 \, \sigma} \, \ln \left( T+1 \right)
$$
$$
\frac{R_T(U)}{T} \ \ \textbf{vanishes at rate } \ \frac{\ln \, T}{T} < < \frac{1}{\sqrt[]{T}} \ \ \textbf{provided } max_t \| \nabla \ell_t (w_t) \| \ \textbf{remains bounded}
$$
We assume it in special case.
\\\\
Where are these SC losses?
\\
Minimising strongly convex version of standard convex losses helps a lot.
\\
We will see how Regularitation imply Stability. Before studing SVM and stability we going to do something before.
\\
\subsection{Relate sequential risk and statistical risk}
It is important: I have this algorith that control sequential risk and regret but I am also courious to use this algorithms.
\\\\
We assume:\\
Data $(x_t,y_) $ drawm i.i.d. from fixed unknown $D$.
\\
Convex loss function $\ell$.
\\ For example compare square loss and hinge loss(convex upper bound on $0$-$1$ $loss$:
$$
\ell(\hat{y}, y = (\hat{y},y)^2 \qquad \ell(\hat{y},y) = \left[ 1- \hat{y} \, y \right]_+
$$
We will focus on linear predictors $h(x) = f(w^T \, x) $\quad (easily to analise with OGD framework).
\\
Risk $\ell_D(w) =$ \expt{\ell(w^T \, X, Y) }
\\
where $ \hat{y} = w^T \, X$
\\
Assume we have a training set $S$ of example $(X_1,Y_1)...(X_m,Y_m)$ \qquad (in maiusc since are random sequence of data point from a distribution)
\\
$$
Convex \quad \ell_t(w) = \ell(w^T \, X_t, Y_t) \qquad t= 1,...m
$$
Became a sequence of convex losses.
\\
I run OGD on $\ell_1,\ell_2,..., \ell_m$ and get $w_1,..., w_m \quad \|w_t\| \leq U$\\
OGD projects onto: $$\{ U \in \barra{R}^d : \| u \| \leq U \} \qquad U^* = arg \min_{u: \|u\| \leq U} \ell_D(u)$$
where $U^*$ is the best linear predictor in class.\\
So i take a bunch of predictors but i need one, so I take the average of those (since the expected value is convex):
$$
\bar{w} = \frac{1}{m}\sum_{t=1}^m w_t
$$
I want to study the variance error:
$$
\ell_D(\bar{w}) - \ell_D(u^*) \ ?
$$
I am using Online Learning.
\\
Using Jensen inequality:
$$
\ell_D(\bar{w}) = \barra{E} \left[ \ell(\bar{w}^T \, X, Y \right] \ \leq \ \barra{E} \left[ \frac{1}{m} \sum_{t=1}^m \ell(w_t^T \, X, Y) \right] = \frac{1}{m} \sum_t \barra{E} \left[ \ell(w_t^T \, X, Y) \right]
$$
where $\barra{E} \left[ \ell(w_t^T \, X, Y) \right]$ is equals to $\ell_D(w_t)$
\\
$$
\ell_D(\bar{w}) \leq \frac{1}{m} \sum_{t=1}^n \ell_D(w_t) \qquad \textbf{for any given training set } (x_1,y_1)...(x_m,y_m) \quad
$$
I want to look at the difference:
$$
\ell_D(w_t) - \ell(w_t^T \, X_t, Y_t)
$$
$
\ell_D = \ $\expt{\ell(w^T_t \, X, Y) }$
$\\
Now I fix $t-1$ example in the training set \quad $(X_1, Y_1) ...(X_{t-1},Y_{t-1})$
\\
$w_t$ is \bred{determined} by $(X_1, Y_1),...(X_{t-1},Y_{t-1})$\\
$(X_t,Y_t)$ is distribuited like any $(X,Y) \sim D$
$$
\barra{E}_{t-1} \left[ \, \cdot \, \right] = \barra{E} \left[ \, \cdot \, | (X_1,Y_1)...(X_{t-1}, Y_{t-1} \right] \qquad z_t = \ell_D(w_t) - \ell( w_t^T \, X_t, Y_t)
$$
$$
\frac{1}{m} \sum_{t=1}^m \barra{E}_{t-1} \left[ Z_t \right] = 0
$$
I want to show the average of $\ell_D(w_t)$ is equal to average of $\ell(w^T_t \, X_t, Y)$
\\
I want to prove:
$$
\frac{1}{m} \sum_{t=1}^m \ell_D (w_t) \ \leq \ \red{\frac{1}{m} \sum_{t=1}^m \ell(w_t^T \, X_t, Y_t)}+ \ \sqrt[]{\frac{1}{m} \, \ln \frac{1}{\delta}} \qquad \textit{ with high probability w.r.t. S}
$$
where (red part) is the sequential risk of OGD.
$$
\frac{1}{m} \sum_{t=1}^m Z_t \leq \sqrt[]{\frac{1}{m} \, \ln \frac{1}{\delta}} \qquad \textbf{with prob. at least $1-\delta$}
$$
I know that $\barra{E}_{t-1} \left[ Z_t\right] = 0 $
$$ |Z_t| \in [0, M] \quad \Rightarrow \quad \frac{1}{m} \sum_{t=1}^m Z_t \leq M \sqrt[]{\frac{2}{m} \, \ln \frac{1}{\delta}} \quad \textit{w.p $1-\delta$}
$$\\
Version of Chernoff-Hoffdiwg bounds for sums of dependent random variables.
\\
$$
\frac{1}{m} \sum_{t=1}^m \ell_D(w_t) \ \leq \ \frac{1}{m} \sum_{t=1}^m \ell_t(w_t) + M \ \sqrt[]{\frac{2}{m} \ln \frac{1}{\delta}} \quad \textit{ w.p $1-\delta$}
$$
\\
This tells me that$ \ell_D(\bar{w})$ is controlled by the sequential risk of OGD + $O \left(\frac{1}{\sqrt[]{m}} \right)$
\\
Variance Error for $(w^T \, x-y)^2 \qquad \| x_t\| \leq X, \quad |y_t| \leq U \, X$
$$
G = \max_t \| \nabla \ell_t (w_t) \| \leq 4\, (U \, X)^2
$$
$$
\ell_D(\bar{w}) \leq \red{ \min_{u: \|u\| \leq U} \frac{1}{m} \sum_{t=1}^m \ell_D(u) + 8 \, (U \, X)^2 \sqrt[]{\frac{2}{m}}}+ 4 \, (U \, X)^2 \ \sqrt[]{\frac{2}{m} \, \ln\frac{1}{\delta}}
$$
where \red{red} is \bred{OGD analysis}
$$
\ell_D(\bar{w}) \ \leq \ \min \frac{1}{m} \sum_{t=1}^m \ell_t(u) + 12 \, (U \, X)^2 \sqrt[]{\frac{2}{m} \, \ln \frac{1}{\delta}} \quad \textit{with prob. $1-\delta$}
$$
By C-H bounds:
$$
where \quad \min \frac{1}{m} \sum_{t=1}^m \ell_t(u) \ \leq \ \frac{1}{m} \sum_{t=1}^m \ell_t(u^*) \ \leq \ \ell_D(u^*) + 4\, (U \, X)^2 \ \sqrt[]{\frac{1}{2 \, m} \ln \, \frac{1}{\delta}}
$$
where the sum is the test error of $u^*$
\\
At the end:
$$
\ell_D(\bar{w}) \leq \ell_D(u^*) + 16 \, (U \, X)^2 \ \sqrt[]{\frac{1}{m} \, \ln \, \frac{1}{\delta}} \qquad \textit{w.p $1-\delta$}
$$
Even with m large, I can run it since i bounded in the small "ball".
\end{document}

View File

@ -183,15 +183,18 @@
\@writefile{toc}{\contentsline {chapter}{\numberline {17}Lecture 17 - 11-05-2020}{108}\protected@file@percent }
\@writefile{lof}{\addvspace {10\p@ }}
\@writefile{lot}{\addvspace {10\p@ }}
\@writefile{toc}{\contentsline {chapter}{\numberline {18}Lecture 18 - 12-05-2020}{109}\protected@file@percent }
\@writefile{toc}{\contentsline {section}{\numberline {17.1}Strongly convex loss functions}{108}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {17.1.1}OGD for Strongly Convex losses}{108}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {17.1.2}Relate sequential risk and statistical risk}{109}\protected@file@percent }
\@writefile{toc}{\contentsline {chapter}{\numberline {18}Lecture 18 - 12-05-2020}{112}\protected@file@percent }
\@writefile{lof}{\addvspace {10\p@ }}
\@writefile{lot}{\addvspace {10\p@ }}
\@writefile{toc}{\contentsline {section}{\numberline {18.1}Kernel functions}{109}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {18.1.1}Feature expansion}{109}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.1}{\ignorespaces }}{109}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {18.1.2}Kernels implements feature expansion (Efficiently}{110}\protected@file@percent }
\@writefile{toc}{\contentsline {section}{\numberline {18.2}Gaussian Kernel}{111}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.2}{\ignorespaces }}{112}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.3}{\ignorespaces }}{112}\protected@file@percent }
\@writefile{toc}{\contentsline {section}{\numberline {18.1}Kernel functions}{112}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {18.1.1}Feature expansion}{112}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.1}{\ignorespaces }}{112}\protected@file@percent }
\@writefile{toc}{\contentsline {subsection}{\numberline {18.1.2}Kernels implements feature expansion (Efficiently}{113}\protected@file@percent }
\@writefile{toc}{\contentsline {section}{\numberline {18.2}Gaussian Kernel}{114}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.2}{\ignorespaces }}{115}\protected@file@percent }
\@writefile{lof}{\contentsline {figure}{\numberline {18.3}{\ignorespaces }}{115}\protected@file@percent }
\bibstyle{abbrv}
\bibdata{main}

View File

@ -89,6 +89,6 @@
\contentsline {figure}{\numberline {16.4}{\ignorespaces Example of more type of convex function}}{106}%
\addvspace {10\p@ }
\addvspace {10\p@ }
\contentsline {figure}{\numberline {18.1}{\ignorespaces }}{109}%
\contentsline {figure}{\numberline {18.2}{\ignorespaces }}{112}%
\contentsline {figure}{\numberline {18.3}{\ignorespaces }}{112}%
\contentsline {figure}{\numberline {18.1}{\ignorespaces }}{112}%
\contentsline {figure}{\numberline {18.2}{\ignorespaces }}{115}%
\contentsline {figure}{\numberline {18.3}{\ignorespaces }}{115}%

View File

@ -1,4 +1,4 @@
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (MiKTeX 2.9.7300 64-bit) (preloaded format=pdflatex 2020.4.13) 16 MAY 2020 12:54
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (MiKTeX 2.9.7300 64-bit) (preloaded format=pdflatex 2020.4.13) 17 MAY 2020 17:34
entering extended mode
**./main.tex
(main.tex
@ -2723,9 +2723,79 @@ Underfull \hbox (badness 10000) in paragraph at lines 196--139
[107] (lectures/lecture17.tex
Chapter 17.
) [108
] (lectures/lecture18.tex
Underfull \hbox (badness 10000) in paragraph at lines 7--12
[]
Underfull \hbox (badness 10000) in paragraph at lines 12--14
[]
Underfull \hbox (badness 10000) in paragraph at lines 16--21
[]
Overfull \hbox (17.19559pt too wide) detected at line 41
\OT1/cmr/m/n/12 +[][] + [][] + [] [] \OML/cmm/m/it/12 []
[]
[108
]
Overfull \hbox (62.05049pt too wide) detected at line 59
[] [] [] \OML/cmm/m/it/12 << [] []max[]\OMS/cmsy/m/n/12 kr\OML/cmm/m/it/12 `[
]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12 )\OMS/cmsy/m/n/12 k []
[]
Underfull \hbox (badness 10000) in paragraph at lines 59--68
[]
Underfull \hbox (badness 10000) in paragraph at lines 59--68
[]
Underfull \hbox (badness 10000) in paragraph at lines 69--76
[]
Underfull \hbox (badness 10000) in paragraph at lines 78--87
[]
[109]
Underfull \hbox (badness 10000) in paragraph at lines 108--111
[]
Overfull \hbox (2.33182pt too wide) detected at line 113
\OML/cmm/m/it/12 `[]\OT1/cmr/m/n/12 ([]) \OMS/cmsy/m/n/12  [] [] \OML/cmm/m/it
/12 `[]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12 ) [](\OML/cmm/m/it/
12 x[]; y[]\OT1/cmr/m/n/12 )\OML/cmm/m/it/12 :::\OT1/cmr/m/n/12 (\OML/cmm/m/it/
12 x[]; y[]\OT1/cmr/m/n/12 )
[]
Overfull \hbox (24.90033pt too wide) detected at line 136
[] [] \OML/cmm/m/it/12 `[]\OT1/cmr/m/n/12 (\OML/cmm/m/it/12 w[]\OT1/cmr/m/n/12
) \OMS/cmsy/m/n/12  [][] \OT1/cmr/m/n/12 + [] []
[]
[110]
Underfull \hbox (badness 10000) in paragraph at lines 143--146
[]
) [111] (lectures/lecture18.tex
Chapter 18.
Underfull \hbox (badness 10000) in paragraph at lines 13--16
@ -2737,7 +2807,7 @@ Underfull \hbox (badness 10000) in paragraph at lines 16--21
[]
<lectures/../img/lez18-img1.JPG, id=450, 381.67593pt x 159.59625pt>
<lectures/../img/lez18-img1.JPG, id=459, 381.67593pt x 159.59625pt>
File: lectures/../img/lez18-img1.JPG Graphic file (type jpg)
<use lectures/../img/lez18-img1.JPG>
Package pdftex.def Info: lectures/../img/lez18-img1.JPG used on input line 29.
@ -2753,7 +2823,7 @@ Underfull \hbox (badness 10000) in paragraph at lines 38--41
[]
[109
[112
<./lectures/../img/lez18-img1.JPG>]
Overfull \hbox (4.83661pt too wide) in paragraph at lines 45--45
@ -2786,7 +2856,7 @@ Underfull \hbox (badness 10000) in paragraph at lines 79--88
[]
[110]
[113]
Underfull \hbox (badness 10000) in paragraph at lines 94--111
[]
@ -2807,7 +2877,7 @@ Overfull \hbox (16.83592pt too wide) detected at line 112
(\OML/cmm/m/it/12 x[]\OT1/cmr/m/n/12 )
[]
<lectures/../img/lez18-img2.JPG, id=457, 716.6775pt x 146.79843pt>
<lectures/../img/lez18-img2.JPG, id=466, 716.6775pt x 146.79843pt>
File: lectures/../img/lez18-img2.JPG Graphic file (type jpg)
<use lectures/../img/lez18-img2.JPG>
Package pdftex.def Info: lectures/../img/lez18-img2.JPG used on input line 124
@ -2831,8 +2901,8 @@ Underfull \hbox (badness 10000) in paragraph at lines 120--128
LaTeX Warning: `h' float specifier changed to `ht'.
[111]
<lectures/../img/lez18-img3.JPG, id=461, 221.32687pt x 176.91093pt>
[114]
<lectures/../img/lez18-img3.JPG, id=471, 221.32687pt x 176.91093pt>
File: lectures/../img/lez18-img3.JPG Graphic file (type jpg)
<use lectures/../img/lez18-img3.JPG>
Package pdftex.def Info: lectures/../img/lez18-img3.JPG used on input line 133
@ -2858,7 +2928,7 @@ Underfull \hbox (badness 10000) in paragraph at lines 147--154
[]
[112 <./lectures/../img/lez18-img2.JPG> <./lectures/../img/lez18-img3.JPG>])
[115 <./lectures/../img/lez18-img2.JPG> <./lectures/../img/lez18-img3.JPG>])
Underfull \hbox (badness 10000) in paragraph at lines 171--145
[]
@ -2868,11 +2938,11 @@ Underfull \hbox (badness 10000) in paragraph at lines 171--145
[]
[113] (main.bbl
[116] (main.bbl
LaTeX Warning: Empty `thebibliography' environment on input line 3.
) [114
) [117
] (main.aux) )
Here is how much of TeX's memory you used:
@ -2911,9 +2981,9 @@ s/cm/cmr8.pfb><C:/Program Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmsy1
/Program Files/MiKTeX 2.9/fonts/type1/public/amsfonts/cm/cmsy8.pfb><C:/Program
Files/MiKTeX 2.9/fonts/type1/public/amsfonts/symbols/msam10.pfb><C:/Program Fil
es/MiKTeX 2.9/fonts/type1/public/amsfonts/symbols/msbm10.pfb>
Output written on main.pdf (115 pages, 2586776 bytes).
Output written on main.pdf (118 pages, 2599444 bytes).
PDF statistics:
977 PDF objects out of 1000 (max. 8388607)
988 PDF objects out of 1000 (max. 8388607)
0 named destinations out of 1000 (max. 500000)
386 words of extra memory for PDF output out of 10000 (max. 10000000)

View File

@ -75,8 +75,11 @@
\contentsline {section}{\numberline {16.1}Analysis of Perceptron in the non-separable case using OGD framework.}{102}%
\contentsline {subsection}{\numberline {16.1.1}Strongly convex loss functions}{106}%
\contentsline {chapter}{\numberline {17}Lecture 17 - 11-05-2020}{108}%
\contentsline {chapter}{\numberline {18}Lecture 18 - 12-05-2020}{109}%
\contentsline {section}{\numberline {18.1}Kernel functions}{109}%
\contentsline {subsection}{\numberline {18.1.1}Feature expansion}{109}%
\contentsline {subsection}{\numberline {18.1.2}Kernels implements feature expansion (Efficiently}{110}%
\contentsline {section}{\numberline {18.2}Gaussian Kernel}{111}%
\contentsline {section}{\numberline {17.1}Strongly convex loss functions}{108}%
\contentsline {subsection}{\numberline {17.1.1}OGD for Strongly Convex losses}{108}%
\contentsline {subsection}{\numberline {17.1.2}Relate sequential risk and statistical risk}{109}%
\contentsline {chapter}{\numberline {18}Lecture 18 - 12-05-2020}{112}%
\contentsline {section}{\numberline {18.1}Kernel functions}{112}%
\contentsline {subsection}{\numberline {18.1.1}Feature expansion}{112}%
\contentsline {subsection}{\numberline {18.1.2}Kernels implements feature expansion (Efficiently}{113}%
\contentsline {section}{\numberline {18.2}Gaussian Kernel}{114}%