why am I receiving "Input data must be a numeric, cell, or logical array." message when I used p= vpa(q) ?

D=[];
Q=[];
for d=3:0.1:5
m=(pi*((d)^2)*8.9)/4;
M=(m/465.96)*1000;
syms t
q=int (m*(103.60+0.034*t),300, 773);
p=vpa(q);
%q in joules
D=[D,d];
Q=[Q,p];
end
xlswrite('C:\sharad\asaas',D','B2:B4902')
xlswrite('C:\sharad\asaas',Q','C2:C4902')

[Ahmet Cecen]

This runs for me without a hitch.

Answer 1

[Star Strider]

I cannot reproduce that error. Your code runs fine for me (in R2016a).

When I add this line after the loop:

DQ = [D; Q]

I get:

DQ =

[                                 3,                             31/10,                              16/5,                             33/10,                              17/5,                               7/2,                              18/5,                             37/10,                              19/5,                             39/10,                                4,                             41/10,                              21/5,                             43/10,                              22/5,                               9/2,                              23/5,                             47/10,                              24/5,                             49/10,                                 5]
[ 3625575.8300848154758568853139877, 3871309.3030127863021334633231163, 4125099.6111187233836972154676914, 4386946.7544026267278240993618965, 4656850.7328644963272381573915482, 4934811.5465043321746634319424629, 5220829.1953221342846518382430077, 5514903.6793179032101761549711227, 5817034.9984916372632142156362534, 6127223.1528433372586732730269432, 6445468.142373005292029120028019, 6771769.9670806377980625256896019, 7106128.6269662383274408057332039, 7448544.1220298032130813226103783, 7799016.4522713363985531032085419, 8157545.6176908348279539495706558, 8524131.6182882994762621819972992, 8898774.4540637318859808146953583, 9281474.1250171276042237877845764, 9672230.6311484935285989195108414, 10071043.972457820782437920570374]

[sharad tiwari]

Thanks for answering but I am still receiving error in line 19 here it says Error using xlswrite (line 166) Input data must be a numeric, cell, or logical array.

Error in heat_vs_diameter_unsuccessful (line 19) xlswrite('C:\sharad\asaas',Q','C2:C4902')

Although when I write what you suggested it worked with same error message. Any suggestion ?

[Star Strider]

My pleasure.

You didn’t mention that the problem was occurring in your xlswrite call. The ‘DQ’ in my code is a sym object. To convert it to a double array, use the double function:

DQ = double([D; Q])

That will work.