Re: [PATCH] attr: map builtin userdiff drivers to well-known extensions

From: Philip Oakley <hidden>
Date: 2016-06-15 22:52:41
Subsystem: the rest · Maintainer: Linus Torvalds

From: "Jeff King" <redacted> Sent: Friday, December 16, 2011 7:32 PM

On Fri, Dec 16, 2011 at 07:26:00PM -0000, Philip Oakley wrote:

quoted

+ "*.m diff=objc",

There is a conflict here with the Matlab community which also uses
"*.m" files for its scripts and code.
They fit the "It's not that hard to do, but it's an extra step that
the user might not even know is an option." rationale.

If the objc.m is used as a default it must be overidable easily, and
listed in the appropriate documentation to mitigate the "might not
even know" risk.

It is easily overridable; just put your own "*.m" (or anything that
matches your files) entry into your gitattributes file. I'm more
concerned that people will start getting worse results than with the
default, and not know how to fix it.

If you have some Matlab files, would you mind doing diffs with the
default driver and with the objc driver, and comment on how good or bad
the results are?

-Peff
--

Sorry for the delay.
I started with a fresh install of Msysgit 1.7.8 for my tests, and created a 
test repo from a set of old project zip files, retaining only the *.m files. 
i.e. it is a real hack project. The diff shown was a small tweak & 
investigation step. Below are the three cases of:
1. plain vanilla install (no .gitattributes file)
2. with *.m=matlab in .gitattributes
3. with *.m=objc in .gitattributes

The "*.m=matlab" does give better (proper) hunk headers as it picks out the 
"^%%" comment line which starts a code block . For option 3 (ObjC) they are 
empty (which is poor). The plain vanila (default) hunk headers are so-so.

There is a vast quantity (10,000+) of Matlab examples on the Mathworks 
(vendor) File exchange web site, if anyone is interested, 
http://www.mathworks.com/matlabcentral/fileexchange/?sort=date_desc_updated&term=

Roughly my command sequence was:
$git diff HEAD HEAD~1  -p > test.txt
#rename test.txt to suitable name

$echo "*.m diff=matlab" >>.gitattributes
#repeat

$echo "*.m diff=objc" >>.gitattributes
#repeat

-----------------
1. plain vanilla install (no .gitattributes file)

diff --git a/detect_and_track.m b/detect_and_track.m
index 0f0356d..69d650f 100644
--- a/detect_and_track.m
+++ b/detect_and_track.m

@@ -161,9 +161,8 @@ sz = [960, 1280]; pixshrink = 10; % 10 is a guess!
 parabolic = pararate(sz(2), pixshrink);

 %% Set up the filters.
-% changed sizes to be an extra pixel all round both inner & outer
-hsize = [15 17]; % [11 13] size of (square) filter [vert horiz]
-inhsize = [7 7] ; % [5 5] size of inner filter
+hsize = [11 13]; % size of (square) filter [vert horiz]
+inhsize = [5 5] ; % size of inner filter
 % siz=[hsize hsize];
 sigma2 = [3.5 4.5]; % outer radius
 sigma3 = [1.4 1.4]; % inner radius

@@ -290,7 +289,7 @@ for TframeNum = FrameRange;  %change this value to read

in a different frame
             % shrink the image
             Image = Shrink2(Image);
         end
-        if any(find(J==[1 2 3 4])) %  5 6 7
+        if any(find(J==[1 2])) %  3 4 5 6 7
             % list the levels you want procesed / rectangles shown
             % i.e. [1 2 3 4 5 6 7]
             [localmean localstdev ] = Point_Filter_cross3(Image,Table);

diff --git a/do_noise_ratios.m b/do_noise_ratios.m
index 663d898..dd73ed0 100644
--- a/do_noise_ratios.m
+++ b/do_noise_ratios.m

@@ -10,7 +10,7 @@

 % NewFrame{J,2}=localstdev; %

-for baselev=1:3;
+for baselev=1:2;
 Noise_Ratio = Stretch2(NewFrame{baselev+1,2}) ./  NewFrame{baselev,2} ;
 Noise_Ratio(Noise_Ratio>5)=5;
 figure(49+baselev); colorbar;


-----------------

2. with *.m=matlab in .gitattributes

diff --git a/detect_and_track.m b/detect_and_track.m
index 0f0356d..69d650f 100644
--- a/detect_and_track.m
+++ b/detect_and_track.m

@@ -161,9 +161,8 @@ %% set up the camera Configurations
 parabolic = pararate(sz(2), pixshrink);

 %% Set up the filters.
-% changed sizes to be an extra pixel all round both inner & outer
-hsize = [15 17]; % [11 13] size of (square) filter [vert horiz]
-inhsize = [7 7] ; % [5 5] size of inner filter
+hsize = [11 13]; % size of (square) filter [vert horiz]
+inhsize = [5 5] ; % size of inner filter
 % siz=[hsize hsize];
 sigma2 = [3.5 4.5]; % outer radius
 sigma3 = [1.4 1.4]; % inner radius

@@ -290,7 +289,7 @@ %% Loop Starts here
             % shrink the image
             Image = Shrink2(Image);
         end
-        if any(find(J==[1 2 3 4])) %  5 6 7
+        if any(find(J==[1 2])) %  3 4 5 6 7
             % list the levels you want procesed / rectangles shown
             % i.e. [1 2 3 4 5 6 7]
             [localmean localstdev ] = Point_Filter_cross3(Image,Table);

diff --git a/do_noise_ratios.m b/do_noise_ratios.m
index 663d898..dd73ed0 100644
--- a/do_noise_ratios.m
+++ b/do_noise_ratios.m

@@ -10,7 +10,7 @@ %% do_noise_ratios

 % NewFrame{J,2}=localstdev; %

-for baselev=1:3;
+for baselev=1:2;
 Noise_Ratio = Stretch2(NewFrame{baselev+1,2}) ./  NewFrame{baselev,2} ;
 Noise_Ratio(Noise_Ratio>5)=5;
 figure(49+baselev); colorbar;


-----------------

3. with *.m=objc in .gitattributes

diff --git a/detect_and_track.m b/detect_and_track.m
index 0f0356d..69d650f 100644
--- a/detect_and_track.m
+++ b/detect_and_track.m

@@ -161,9 +161,8 @@
 parabolic = pararate(sz(2), pixshrink);

 %% Set up the filters.
-% changed sizes to be an extra pixel all round both inner & outer
-hsize = [15 17]; % [11 13] size of (square) filter [vert horiz]
-inhsize = [7 7] ; % [5 5] size of inner filter
+hsize = [11 13]; % size of (square) filter [vert horiz]
+inhsize = [5 5] ; % size of inner filter
 % siz=[hsize hsize];
 sigma2 = [3.5 4.5]; % outer radius
 sigma3 = [1.4 1.4]; % inner radius

@@ -290,7 +289,7 @@
             % shrink the image
             Image = Shrink2(Image);
         end
-        if any(find(J==[1 2 3 4])) %  5 6 7
+        if any(find(J==[1 2])) %  3 4 5 6 7
             % list the levels you want procesed / rectangles shown
             % i.e. [1 2 3 4 5 6 7]
             [localmean localstdev ] = Point_Filter_cross3(Image,Table);

diff --git a/do_noise_ratios.m b/do_noise_ratios.m
index 663d898..dd73ed0 100644
--- a/do_noise_ratios.m
+++ b/do_noise_ratios.m

@@ -10,7 +10,7 @@

 % NewFrame{J,2}=localstdev; %

-for baselev=1:3;
+for baselev=1:2;
 Noise_Ratio = Stretch2(NewFrame{baselev+1,2}) ./  NewFrame{baselev,2} ;
 Noise_Ratio(Noise_Ratio>5)=5;
 figure(49+baselev); colorbar;

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