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Professional Interests: Mathematical Computing

Answered

How do I turn of thr grid of a surface but keep the edge line on?

[X,Y] = meshgrid(1:10) ; Z = sqrt(X.^2+Y.^2) ; % plot the outer line X1 = X ; X1(2:end-1,2:end-1) = NaN ; Y1 = Y ; Y1(...

How do I turn of thr grid of a surface but keep the edge line on?

[X,Y] = meshgrid(1:10) ; Z = sqrt(X.^2+Y.^2) ; % plot the outer line X1 = X ; X1(2:end-1,2:end-1) = NaN ; Y1 = Y ; Y1(...

19 hours ago | 0

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Answered

How do I subplot multiple tiles that I divided from a satellite image in one figure?

count = 0 ; for m=1:16 for n=1:16 count = count+1 ; subplot(16,16,count); imshow(tiles{m,n}); ...

How do I subplot multiple tiles that I divided from a satellite image in one figure?

count = 0 ; for m=1:16 for n=1:16 count = count+1 ; subplot(16,16,count); imshow(tiles{m,n}); ...

21 hours ago | 1

Answered

Changing the color of a 3D plot

This command: h = plot( fitresult); You specify a marker/ different color for both the functions. h = plot( fitresult,'b'); ...

Changing the color of a 3D plot

This command: h = plot( fitresult); You specify a marker/ different color for both the functions. h = plot( fitresult,'b'); ...

21 hours ago | 0

Answered

Select points inside a polygon

You can use the previous questions answer..with a slight change while saving the points. clc; clear all ; load("polygon1_x.ma...

Select points inside a polygon

You can use the previous questions answer..with a slight change while saving the points. clc; clear all ; load("polygon1_x.ma...

21 hours ago | 1

Answered

Velocity potential with quiver command

You should use gradient. [u,v] = gradient(StreamFunction) ; quiver(x,y,u,v)

Velocity potential with quiver command

You should use gradient. [u,v] = gradient(StreamFunction) ; quiver(x,y,u,v)

22 hours ago | 0

Answered

Plot a box around set of points

This question can be solved from your previous question which was answered. If (x,y) is your point and you want points around ...

Plot a box around set of points

This question can be solved from your previous question which was answered. If (x,y) is your point and you want points around ...

22 hours ago | 1

Answered

how can i plot positive magnitude only of a sine wave

% get the index of only positive values idx = DC_Voltage>=0 ; plot(DC_Voltage(idx))

how can i plot positive magnitude only of a sine wave

% get the index of only positive values idx = DC_Voltage>=0 ; plot(DC_Voltage(idx))

23 hours ago | 1

Answered

i was writing a equation but this always have an error and i cant run it

You should first define the constants and then type the formula. T= 1000; L=10; W=100; S=100000; %% this is tha value of ...

i was writing a equation but this always have an error and i cant run it

You should first define the constants and then type the formula. T= 1000; L=10; W=100; S=100000; %% this is tha value of ...

23 hours ago | 1

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Answered

Create a box around points and use in inpolygon

load("polygon1_x.mat") ; load("polygon1_y.mat") ; load("lon.mat") ; load("lat.mat") ; % remove Nan's from the data xv ...

Create a box around points and use in inpolygon

load("polygon1_x.mat") ; load("polygon1_y.mat") ; load("lon.mat") ; load("lat.mat") ; % remove Nan's from the data xv ...

1 day ago | 1

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Answered

How to use ginput to determine the coordinates of an image

You have dimensions of each image...say dimensions of each image [m,n,3]. Initiate a matrix idx such that, each quarter has the ...

How to use ginput to determine the coordinates of an image

You have dimensions of each image...say dimensions of each image [m,n,3]. Initiate a matrix idx such that, each quarter has the ...

2 days ago | 0

Answered

how can i write the code out for this 1-1/2+1/3-1/4+1/5-,.....

It is your Home work..you have to do it. Do the following. Read about for loop. Fix the value of n, to run a loop. You can...

how can i write the code out for this 1-1/2+1/3-1/4+1/5-,.....

It is your Home work..you have to do it. Do the following. Read about for loop. Fix the value of n, to run a loop. You can...

3 days ago | 0

Answered

How to find the exact index(row, col) of a maximum value in a matrix?

Let I be your image. [m,n,p] = size(I) ; x = 1:n ; y = 1:m ; [X,Y] = meshgrid(x,y) ; [val,idx] = max(I(:)) ; imshow(I...

How to find the exact index(row, col) of a maximum value in a matrix?

Let I be your image. [m,n,p] = size(I) ; x = 1:n ; y = 1:m ; [X,Y] = meshgrid(x,y) ; [val,idx] = max(I(:)) ; imshow(I...

4 days ago | 0

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Answered

strength of materials in matlab

P = [0 0] ; L = 1000 ; % length of beam B = 0.5 ; % breadth of beam B = [P ; L P(2) ; L B ; P(1) B] ; patch(B(:...

strength of materials in matlab

P = [0 0] ; L = 1000 ; % length of beam B = 0.5 ; % breadth of beam B = [P ; L P(2) ; L B ; P(1) B] ; patch(B(:...

4 days ago | 0

Answered

How to make a contour plot with data from using ode45

X= linspace(1,5,5); % Vector for alpha_p values Y= linspace(0.5,3,5); % Vector for beta_p values [A, B]= meshgrid(X,Y); nt ...

How to make a contour plot with data from using ode45

X= linspace(1,5,5); % Vector for alpha_p values Y= linspace(0.5,3,5); % Vector for beta_p values [A, B]= meshgrid(X,Y); nt ...

4 days ago | 0

Answered

Find the general solution of the equation y ′ − y = y 2 e x .

syms y(x) ode = diff(y,x)-y==y^2*exp(x) ; sol = dsolve(ode)

Find the general solution of the equation y ′ − y = y 2 e x .

syms y(x) ode = diff(y,x)-y==y^2*exp(x) ; sol = dsolve(ode)

6 days ago | 0

Answered

Let A and B be square matrices of same order. Prove that characteristic polynomials of AB and BA are same. Do AB and BA have same minimal polynomial ?

Calculate the eigenvalues of the product. They will be euqal. A = rand(2) ; B = rand(2) ; AB = eig(A*B) BA = eig(B*A)

Let A and B be square matrices of same order. Prove that characteristic polynomials of AB and BA are same. Do AB and BA have same minimal polynomial ?

Calculate the eigenvalues of the product. They will be euqal. A = rand(2) ; B = rand(2) ; AB = eig(A*B) BA = eig(B*A)

6 days ago | 0

Answered

if(0.41 == (41*0.01)) is False and if(0.42 == (42*0.01)) is True .. Why?

Read about comparing floating-point numbers. tol = 10^-5 ; if(abs(0.41-(41*0.01)<=tol)) %First Condition disp('tr...

if(0.41 == (41*0.01)) is False and if(0.42 == (42*0.01)) is True .. Why?

Read about comparing floating-point numbers. tol = 10^-5 ; if(abs(0.41-(41*0.01)<=tol)) %First Condition disp('tr...

6 days ago | 0

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Answered

Error: Brace indexing is not supported for variables of this type.

datevec = cell2mat(datenum); Or check class(datenum) It should be already a converted to double.

Error: Brace indexing is not supported for variables of this type.

datevec = cell2mat(datenum); Or check class(datenum) It should be already a converted to double.

6 days ago | 0

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Answered

Sum of two numbers is not accepted

Read about comparing two floating-point numbers. a=0.14+0.001; tol = 10^-5 ; idx = abs(M(:,2)-a)<=tol ; M(idx,:)=[];

Sum of two numbers is not accepted

Read about comparing two floating-point numbers. a=0.14+0.001; tol = 10^-5 ; idx = abs(M(:,2)-a)<=tol ; M(idx,:)=[];

6 days ago | 0

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Answered

How to remove the grid from plot

x = linspace(0,10); [X,Y] = meshgrid(x,x); z = X.*Y; pcolor(x,x,z); shading interp

How to remove the grid from plot

x = linspace(0,10); [X,Y] = meshgrid(x,x); z = X.*Y; pcolor(x,x,z); shading interp

6 days ago | 1

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Answered

Matrix dimensions must agree error

Ws=2*pi*60; tetha=0; t=0:0.0001:0.1; v1=linspace(1,30,length(t)); % it can be v1=1:1:30 N=45; I=10; p=2; K =(2*N*I)/(pi*...

Matrix dimensions must agree error

Ws=2*pi*60; tetha=0; t=0:0.0001:0.1; v1=linspace(1,30,length(t)); % it can be v1=1:1:30 N=45; I=10; p=2; K =(2*N*I)/(pi*...

6 days ago | 0

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Answered

How can I plot a unit vector in 3-D space?

You need not to use that complex, time consuming loop to get what you want. clear all close all clc N=101; x=linspace(-10,...

How can I plot a unit vector in 3-D space?

You need not to use that complex, time consuming loop to get what you want. clear all close all clc N=101; x=linspace(-10,...

6 days ago | 0

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Answered

mean over over multiple dimensions and multiple arrays

% make dummy data N = 8 ; for i = 1:N C{i} = rand(2,2,3) ; end % get the mean N = length(C) ; [m,n,p] = size(C{1})...

mean over over multiple dimensions and multiple arrays

% make dummy data N = 8 ; for i = 1:N C{i} = rand(2,2,3) ; end % get the mean N = length(C) ; [m,n,p] = size(C{1})...

6 days ago | 1

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Answered

How to extract a 1D dose at certain depth in x,y or z-direction from a 3D array?

I feel slice is your function.... load("xdim.mat") ; load("ydim.mat") ; load("zdim.mat") ; load("3d_dose data.mat") ; ...

How to extract a 1D dose at certain depth in x,y or z-direction from a 3D array?

I feel slice is your function.... load("xdim.mat") ; load("ydim.mat") ; load("zdim.mat") ; load("3d_dose data.mat") ; ...

6 days ago | 0

Answered

Sum of elements in cell array

Better use loop to avoid confusion using cellfun. Note cellfun also use loop inside. clc; clear all ; load("numerical.mat"); ...

Sum of elements in cell array

Better use loop to avoid confusion using cellfun. Note cellfun also use loop inside. clc; clear all ; load("numerical.mat"); ...

6 days ago | 0

Answered

3D plot on 3D matrix

You can use pcolor/ surf. You can plot w.r.t indices. val = rand(10,5,2) ; % using pcolor subplot(211) pcolor(val(:,:,1))...

3D plot on 3D matrix

You can use pcolor/ surf. You can plot w.r.t indices. val = rand(10,5,2) ; % using pcolor subplot(211) pcolor(val(:,:,1))...

7 days ago | 0

Answered

How to find the point at which a line becomes perpendicular to another line?

x = [150 0] y = [0 150] C = [0 0] ; % get the line ax+by+c = 0 slope = diff(y)/diff(x) ; % slope a = slope ; b = -1...

How to find the point at which a line becomes perpendicular to another line?

x = [150 0] y = [0 150] C = [0 0] ; % get the line ax+by+c = 0 slope = diff(y)/diff(x) ; % slope a = slope ; b = -1...

7 days ago | 0

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Answered

Inserting a row in a matrix in a precise place

A = [ 2 8 3 11 ; 13 33 4 5 ; 18 8 4 7 ; 23 4 6 11 ] ; b = [ 8 4 23 9 ] ; idx = find(A(:,1)<b(1))+1 ; % get the positon whe...

Inserting a row in a matrix in a precise place

A = [ 2 8 3 11 ; 13 33 4 5 ; 18 8 4 7 ; 23 4 6 11 ] ; b = [ 8 4 23 9 ] ; idx = find(A(:,1)<b(1))+1 ; % get the positon whe...

7 days ago | 0