Save a vector constructed inside a loop?

Questions
1

Hello everyone. I am working in a problem in which a for loop with k iterations is present. Inside of said loop, a vector of length l is constructed and displayed on the screen. I, however, need to store those k vectors. I have attempted to construct a matrix of zeros of size k*l outside the loop as

ShannonSavedX = ConstantArray[0, {l, k}];

And then, inside of the for loop, using the letter i as index I try to store the vector in question inside of the matrix as

ShannonSavedX[[All, i]] = shannonIPEPSX

being shannonIPEPSX the name of the vector in question. If I write

Dimensions[shannonIPEPS]

The output is {121}, the value of l in this case. If I write (before the loop)

Dimensions[ShannonSavedX]

The output is {121, 3}. However, if I try to plot the results after, they don’t coincide with the screen output, which is the correct one. The output are nine identical rows, each one containing what should be each of the columns of ShannonSavedX.

Can someone please help me with this?
Thanks.

saved_results.png
saved_results.png1893×332 101 KB

screen_output.png
screen_output.png1368×681 143 KB

2

You haven’t shown all your code. The usual method for doing this kind of problem is to use Table to evaluate the expression and construct a matrix of the results. Loops are rarely an effective way to get a job done in Mathematica.

3

Don’t use a For loop, use Table.

saved = Table[RandomInteger[i, 5], {i, 1, 5}]

Replace RandomInteger with whatever calculates the vectors.

4

Thanks for yout kind answers. Hoever, I am afraid that my loop is complex. This is how my code looks:

For[i = 3, i < countMax + 3, i++,
 
 Xpos = aaa[[All, 1]]; Ypos = aaa[[All, 2]]; 
 windXVal = aaa[[All, i]]; 
 windXMat = Transpose[{Xpos, Ypos, windXVal}]; 
 Print[ListContourPlot[windXMat //. {x_List} :> x, 
   PlotLegends -> Automatic]]; 
 ifuncEPSX = Interpolation[ windXMat //. {x_List} :> x]; 
 Print[ContourPlot[ifuncEPSX[t, u], {t, -75, 0}, {u, 30, 65}, 
   GridLines -> {{xmin, xmax}, None}, PlotLegends -> Automatic]]; 
 intDataVectorEPSX = 
  Flatten[Table[{t, u, ifuncEPSX[t, u]}, {t, xmin, xmax, dDeltaX}, {u,
      ymin, ymax, dDeltaY}]]; leEPS = Length@intDataVectorEPSX; 
 vectorXintEPS = Table[intDataVectorEPSX[[i]], {i, 1, leEPS - 2, 3}]; 
 vectorYintEPS = Table[intDataVectorEPSX[[i]], {i, 2, leEPS - 1, 3}]; 
 vectorFintEPSX = Table[intDataVectorEPSX[[i]], {i, 3, leEPS, 3}]; 
 interpolatedDataEPSX = 
  Transpose[{vectorXintEPS, vectorYintEPS, vectorFintEPSX}]; 
 shannonIPEPS[t_, u_] = 
  Total[#3* sinc[(t - #1)/dDeltaX]*sinc[(u - #2)/dDeltaY] & @@@ 
    interpolatedDataEPSX];
 Print[shannonIPEPS[t_, u_]]; 
 Print[ContourPlot[
   shannonIPEPS[t, u], {t, xmin, xmax}, {u, ymin, ymax}, 
   GridLines -> {{xmin, xmax}, None}, PlotLegends -> Automatic]]; 
 ShannonSavedX[[All, i - 2]] = shannonIPEPS[t_, u_]]

Since I am working with such a complex operation I don’t know where to use the table. Can you please indicate me how to do it?

Thanks again.
Jaime.

5

See if you can adapt this

saved=Table[
  Xpos = aaa[[All, 1]]; Ypos = aaa[[All, 2]]; windXVal = aaa[[All, i]]; 
  windXMat = Transpose[{Xpos, Ypos, windXVal}]; 
  ifuncEPSX = Interpolation[ windXMat //. {x_List} :> x]; 
  intDataVectorEPSX = Flatten[Table[{t, u, ifuncEPSX[t, u]}, {t, xmin, xmax, dDeltaX}, {u,ymin, ymax, dDeltaY}]];
  leEPS = Length@intDataVectorEPSX; 
  vectorXintEPS = Table[intDataVectorEPSX[[i]], {i, 1, leEPS - 2, 3}]; 
  vectorYintEPS = Table[intDataVectorEPSX[[i]], {i, 2, leEPS - 1, 3}]; 
  vectorFintEPSX = Table[intDataVectorEPSX[[i]], {i, 3, leEPS, 3}]; 
  interpolatedDataEPSX = Transpose[{vectorXintEPS, vectorYintEPS, vectorFintEPSX}]; 
  Total[#3* sinc[(t - #1)/dDeltaX]*sinc[(u - #2)/dDeltaY] & @@@ interpolatedDataEPSX],
  {i,3,countMax+2}]
6

Thank you so much. The output is just what I need. I will try to understand what you have written. Thank you so much.

Regards.

Jaime.