Suggestions to improve script performance?

Question

Roger Breton 2022-1-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1635325-suggestions-to-improve-script-performance

编辑： Cris LaPierre 2022-1-28

采纳的回答： Cris LaPierre

在 MATLAB Online 中打开

This is the result of my script, graphically :

It's not a DaVinci but it's 'working'. I tried to use what I thought was Matlab "good" techniques but I'm sure I'm light years behind what good programmers would do... I suspect there are lot's of opportunities for improvements in my code and I would be grateful if you could point out the way. Just a few tips, I'm sure, will go a long way towards getting the improvements I'm looking for. It's not the end of the world, as it is, but you'll see, when you try out the code, that each 'presses' on the Slider takes a long time to execute :

clc
global Axe_a_b;
fig=figure('Name','Roger Breton sRGB CIE ab diagram');
Test = fig.Position;
fig.Position = [1600 500 700 700];
ax = axes(fig);
axis([-128 128 -128 128]);
xticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);
yticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]); 
hold on;
CIE_a = 128;
CIE_b = 65; % 128 / 65, Steps of 4
% Algorithm :
% Each call to the function calculates a new colormap
% using a lower b* value
% Keeping L* range constant, between each function call : 
% Slice L* = 50
Axe_L = transpose(linspace(50, 50, 65)); 
% Create one Column vector of 65 constant a* values,
% to fill the diagram, columns by columns,
% from Left (a* = -128) to right (a* = 128)
Axe_a_b = transpose(linspace(-128, 128, 65));
% MarkerSize = 100
for row = 1:65 
    Col = linspace(CIE_a, CIE_a, 65)';
    RowX=[Axe_a_b, Col];
    colorListAB = CalculateColorList(CIE_a, CIE_b, Axe_L)
    scatter(RowX(:,1),RowX(:,2),100, colorListAB, 'filled', 's');   
    CIE_a = CIE_a - 4;
end
uicontrol('Style', 'Slider', 'Position',[655 500 20 150], 'Value', 0.5, 'Callback', {@sliderCB});
global txt_ctrl;
txt_ctrl = uicontrol('Style', 'text', 'Position',[640 450 50 50], 'String', ['50']);
set(txt_ctrl, 'FontSize', 20);
function [colorListAB] = CalculateColorList(CIE_a,CIE_b, Axe_L)
    % CIE_a = Row
    % CIE_b = Col
    
    global Axe_a_b;
    
    % Create one Column vector of 65 constant a* values
    % 1st call = a* 128
    % 2nd call = a* 124
    % 3rd call = a* 120 ...
    Axe_L_ROW = transpose(linspace(CIE_a, CIE_a, CIE_b)); 
    
    Lab_Axe_AB = [Axe_L, Axe_a_b, Axe_L_ROW]; 
    RGB_Axe_AB = lab2rgb(Lab_Axe_AB) 
    [row,col] = size(RGB_Axe_AB);
    % Process Green/Magenta axis first
    for ROW = 1:row     
         if RGB_Axe_AB(ROW,1) < 0
            RGB_Axe_AB(ROW,1) = 0;
            % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
         if RGB_Axe_AB(ROW,1) > 1
            RGB_Axe_AB(ROW,1) = 1;
            % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
         
         if RGB_Axe_AB(ROW,2) < 0
            RGB_Axe_AB(ROW,2) = 0;
            % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
          if RGB_Axe_AB(ROW,2) > 1
            RGB_Axe_AB(ROW,2) = 1;
            % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
         if RGB_Axe_AB(ROW,3) < 0
            RGB_Axe_AB(ROW,3) = 0;
                        % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
         
         if RGB_Axe_AB(ROW,3) > 1
            RGB_Axe_AB(ROW,3) = 1;
            % Show white color for out of gamut colors
            RGB_Axe_AB(ROW,1) = 0.5;
            RGB_Axe_AB(ROW,2) = 0.5;
            RGB_Axe_AB(ROW,3) = 0.5;
         end
     end
    RGB_Axe_AB_ColorMap = colormap(RGB_Axe_AB) 
    colormapAB = RGB_Axe_AB_ColorMap; 
    colorListAB = colormapAB;   
end
function sliderCB(SliderH, EventData)
    
    global txt_ctrl;
    global Axe_a_b;
    
    CIE_a = 128;
    CIE_b = 65;
    % Retrieve slider current value of 
    Slider_L_New = SliderH.Value * 100; 
        
    set(txt_ctrl,'String',num2str(round(Slider_L_New)));
    Axe_L_New = transpose(linspace(Slider_L_New, Slider_L_New, 65));
     
    for row = 1:65 
        Col = linspace(CIE_a, CIE_a, 65)';
        RowX=[Axe_a_b, Col];
        colorListAB = CalculateColorList(CIE_a, CIE_b, Axe_L_New)
        scatter(RowX(:,1),RowX(:,2),100, colorListAB, 'filled', 's');   
        CIE_a = CIE_a - 4;
    end
end

Any help is appreciated.

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Steven Lord 2022-1-26

在 MATLAB Online 中打开

To generate a vector of constant values you can use repmat, ones, or zeros.

v1 = repmat(42, 1, 5)
v1 = 1×5
    42    42    42    42    42
v2 = 42 + zeros(1, 5)
v2 = 1×5
    42    42    42    42    42
v3 = 42 * ones(1, 5)
v3 = 1×5
    42    42    42    42    42

You can also look at the functions listed in the See Also section on the documentation pages for those functions for other related functions.

Roger Breton 2022-1-28

Ah! So many little "details" to learn....... Thanks!!!!!!

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Answer 1

Cris LaPierre 2022-1-25

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1635325-suggestions-to-improve-script-performance#answer_881910

编辑：Cris LaPierre 2022-1-26

在 MATLAB Online 中打开

You can get around using for loops if you meshgrid your X and Y vectors. I don't love the globals, either. Another way to speed up your code is minimize what gets printed to the screen. Here is what I had time to put together for you.

Note that the control code works, but I had to comment it out to get the code to run in this platform.

fig=figure('Name','Roger Breton sRGB CIE ab diagram');

Test = fig.Position;

fig.Position = [1600 500 700 700];

ax = axes(fig);

axis([-128 128 -128 128]);

xticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

yticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

CIE_a = 128;

CIE_b = 65; % 128 / 65, Steps of 4

% Algorithm :

Axe_L = 50;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

colorListAB = CalculateColorList(X, Y, Axe_L);

scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

%% Works, but commenting out because can't be used in this platform

% txt_ctrl = uicontrol('Style', 'text', 'Position',[640 450 50 50], 'String', ['50']);

% set(txt_ctrl, 'FontSize', 20);

%

% uicontrol('Style', 'Slider', 'Position',[655 500 20 150], 'Value', 0.5, 'Callback', {@sliderCB,txt_ctrl});

function [colorListAB] = CalculateColorList(X,Y, Axe_L)

Axe_L = ones(size(X))*Axe_L;

Lab_Axe_AB = [Axe_L(:), Y(:), X(:)];

RGB_Axe_AB = lab2rgb(Lab_Axe_AB);

ind1 = min(RGB_Axe_AB,[],2);

ind2 = max(RGB_Axe_AB,[],2);

RGB_Axe_AB(ind1<0,:) = 0.5;

RGB_Axe_AB(ind2>1,:) = 0.5;

colorListAB = colormap(RGB_Axe_AB);

end

function sliderCB(SliderH, EventData,txt_ctrl)

CIE_a = 128;

CIE_b = 65;

% Retrieve slider current value of

Slider_L_New = SliderH.Value * 100;

set(txt_ctrl,'String',num2str(round(Slider_L_New)));

Axe_L_New = Slider_L_New;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

colorListAB = CalculateColorList(X, Y, Axe_L_New);

scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

end

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Cris LaPierre 2022-1-26

在 MATLAB Online 中打开

'This' platform = running the code here (in Answers code block)

See the error message below.

fig=figure('Name','Roger Breton sRGB CIE ab diagram');

Test = fig.Position;

fig.Position = [1600 500 700 700];

ax = axes(fig);

axis([-128 128 -128 128]);

xticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

yticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

CIE_a = 128;

CIE_b = 65; % 128 / 65, Steps of 4

% Algorithm :

Axe_L = 50;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

colorListAB = CalculateColorList(X, Y, Axe_L);

scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

%% Works, but commenting out because can't be used in this platform

txt_ctrl = uicontrol('Style', 'text', 'Position',[640 450 50 50], 'String', ['50']);

Error using uicontrol
This functionality is not available on remote platforms.

set(txt_ctrl, 'FontSize', 20);

uicontrol('Style', 'Slider', 'Position',[655 500 20 150], 'Value', 0.5, 'Callback', {@sliderCB,txt_ctrl});

function [colorListAB] = CalculateColorList(X,Y, Axe_L)

Axe_L = ones(size(X))*Axe_L;

Lab_Axe_AB = [Axe_L(:), Y(:), X(:)];

RGB_Axe_AB = lab2rgb(Lab_Axe_AB);

ind1 = min(RGB_Axe_AB,[],2);

ind2 = max(RGB_Axe_AB,[],2);

RGB_Axe_AB(ind1<0,:) = 0.5;

RGB_Axe_AB(ind2>1,:) = 0.5;

colorListAB = colormap(RGB_Axe_AB);

end

function sliderCB(SliderH, EventData,txt_ctrl)

CIE_a = 128;

CIE_b = 65;

% Retrieve slider current value of

Slider_L_New = SliderH.Value * 100;

set(txt_ctrl,'String',num2str(round(Slider_L_New)));

Axe_L_New = Slider_L_New;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

colorListAB = CalculateColorList(X, Y, Axe_L_New);

scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

end

Cris LaPierre 2022-1-26

编辑：Cris LaPierre 2022-1-26

在 MATLAB Online 中打开

Stephen makes a great suggestion. If you make your scatter figure full screen, you see dots. However, that doesn't happen with an image. You need to do some reshaping of the array, and I'm sure with more time you could clean things up, but here's a rough first pass.

Note that, in images, (0,0) is the top left, not botton left, so axis xy is used to make the output the same as what you had before.

fig=figure('Name','Roger Breton sRGB CIE ab diagram');

Test = fig.Position;

fig.Position = [1600 500 700 700];

ax = axes(fig);

axis([-128 128 -128 128]);

xticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

yticks([-128 -112 -96 -80 -64 -48 -32 -16 0 16 32 48 64 80 96 112 128]);

CIE_a = 128;

CIE_b = 65; % 128 / 65, Steps of 4

% Algorithm :

Axe_L = 50;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

% colorListAB = CalculateColorList(X, Y, Axe_L);

% scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

colorListAB = CalculateColorList(Y,X,Axe_L);

colorListAB = reshape(colorListAB,CIE_b,CIE_b,3);

image(X(1,:),Y(:,1),colorListAB)

axis xy

%% Works, but commenting out because can't be used in this platform

% txt_ctrl = uicontrol('Style', 'text', 'Position',[640 450 50 50], 'String', ['50']);

% set(txt_ctrl, 'FontSize', 20);

%

% uicontrol('Style', 'Slider', 'Position',[655 500 20 150], 'Value', 0.5, 'Callback', {@sliderCB,txt_ctrl});

function [colorListAB] = CalculateColorList(X,Y, Axe_L)

Axe_L = ones(size(X))*Axe_L;

Lab_Axe_AB = [Axe_L(:), Y(:), X(:)];

RGB_Axe_AB = lab2rgb(Lab_Axe_AB);

ind1 = min(RGB_Axe_AB,[],2);

ind2 = max(RGB_Axe_AB,[],2);

RGB_Axe_AB(ind1<0,:) = 0.5;

RGB_Axe_AB(ind2>1,:) = 0.5;

colorListAB = colormap(RGB_Axe_AB);

end

function sliderCB(SliderH, EventData,txt_ctrl)

CIE_a = 128;

CIE_b = 65;

% Retrieve slider current value of

Slider_L_New = SliderH.Value * 100;

set(txt_ctrl,'String',num2str(round(Slider_L_New)));

Axe_L_New = Slider_L_New;

Axe_a_b = linspace(-128, 128, 65);

[X,Y] = meshgrid(Axe_a_b,Axe_a_b);

% colorListAB = CalculateColorList(X, Y, Axe_L_New);

% scatter(Y(:),X(:),100, colorListAB, 'filled', 's');

colorListAB = CalculateColorList(Y,X,Axe_L_New);

colorListAB = reshape(colorListAB,CIE_b,CIE_b,3);

image(X(1,:),Y(:,1),colorListAB)

axis xy

end

Roger Breton 2022-1-28

在 MATLAB Online 中打开

I was able to figure out the workings of most instructions but not this one :

RGB_Axe_AB(ind1<0,:) = 0.5;

As far as I can tell, this is using the ind1 array to change all values in RGB_Axe_AB that are below Zero, to 0.5 but I confess I'm struggling with the 'notation' : the colon operator represents all rows? In other words, this is changing all rows values to 0.5 for the elements that are less than Zero?

I'll try to generate a dataset where I can witness the behavior of this operation...

Cris LaPierre 2022-1-28

编辑：Cris LaPierre 2022-1-28

在 MATLAB Online 中打开

This replaced all your if statements for when any value in a row was <0. The colon here indicates all columns, not rows.

There are two steps to doing this.

ind1 = min(RGB_Axe_AB,[],2); % returns the min value in each row
ind2 = max(RGB_Axe_AB,[],2); % returns the max value in each row
% identifies each row where the min is <0. 
% Changes all values in the corresponding row of RGB_Axe_AB to 0.5
RGB_Axe_AB(ind1<0,:) = 0.5; 
% identifies each row where the max is >1. 
% Changes all values in the corresponding row of RGB_Axe_AB to 0.5
RGB_Axe_AB(ind2>1,:) = 0.5;

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Answer 2

Benjamin Thompson 2022-1-25

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1635325-suggestions-to-improve-script-performance#answer_881785

The MATLAB editor has some helpful suggestions, removing unnecessary output and so on. Have you tried using the Profile button in the editor to run it and find the places where the most time is spent?

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Stephen23 2022-1-26

Images are just arrays. Take a look here: https://www.mathworks.com/help/matlab/creating_plots/image-types.html#f2-12468

Updating a IMAGE graphics object would be much more efficient than what you are doing now:

https://www.mathworks.com/help/matlab/creating_plots/the-image-object-and-its-properties.html

Roger Breton 2022-1-26

I have no hesitation to believe you!!

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Suggestions to improve script performance?

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