MATLAB: Is there a way to create and preallocate for tables with a large number of variables (can all be of same type e.g. double) without having to specify each variable independently

create tables with large numbers of variablesMATLAB

I want to create tables with a large number of variables (i.e. many columns of data all of type double) so using for example

sz =[1000,1000]; vartype = {'double','double',….,'double'}; T = table{'Size',sz,'VariableTypes',vartype};

is not reasonable. I assume there's an easier way to do this (i.e. without having to write 'double' thousands of times), but haven't been able to find it. Any suggestions would be appreciated.

Best Answer

sz =[1000,1000]; 
vartype = repmat({'double'},1,sz(2)) ; 
T = table('Size',sz,'VariableTypes',vartype);

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MATLAB: Subscripted assignment dimension mismatch for table variable

I dont know how to define it from size but there's an other way

T_partialdata = table([1;2;3],[4,4;5,5;6,6],[7;8;9])
sz = [10 3];
varTypes = {'double','double','double'};
T = table('Size', sz, 'VariableTypes', varTypes, 'VariableNames', {'A','B','C'});
T.B = zeros(sz(1),2); % defining the size of variable 
T(1:3,:) = T_partialdata

MATLAB: Double integration problem (can not use symbolic math tool box)

You have a couple of errors. One is you didn't define the base recursion functions to be functions but doubles - this is where your error comes from. Second you didn't use .^ everywhere instead of ^.

clc;
   sig=0.5;      
   L=4;            
   k=1.0472;
   k_sig=k*sig;
   kls=k*ls;
     er=3.5;
     theta=(0:10:70)';       
     g=length(theta);
     Q=zeros(g,1);
for i=1:g;
     cs=cosd(theta(i)); s=sind(theta(i)); s2=s.*s; cs2=cs.*cs;
     ks=k.*sig; kL=k.*L; ks2=ks.*ks; kL2=kL.*kL;
     %(*Integration variables*)
     r2=@(r)(r.*r); sf=@(phi)sin(phi); csf=@(phi)cos(phi); 
     rx=@(r,phi)(r.*csf(phi)); ry=@(r,phi)(r.*sf(phi));
Wmh=@(x,y) 0; Wnh=@(x,y) 0*x;
for n=1:4;
      for m=1:4;
        wn=@(r,phi)(n.*kL2./(n.*n + kL2.*((rx(r,phi) - s).^2  ...
                    + ry(r,phi).^2)).^1.5);     
        wm=@(r,phi)(m.*kL2./(m.*m + kL2.*((rx(r,phi) + s).^2 ...
             + ry(r,phi).^2)).^1.5);     
        vhmn=((ks2.*cs2).^(n+m))./(factorial(m).*factorial(n));
        Wm=@(r,phi)(vhmn.*wn(r,phi).*wm(r,phi));
        Wmh=@(r,phi)(Wmh(r,phi)+Wm(r,phi));
      end
end
   Wnh=@(r,phi)(Wnh(r,phi)+Wmh(r,phi));
   VH=@(r,phi)(Wnh(r,phi).*r);
%%Double Integration
   Q(i)=quad2d(VH,0,1,0,pi/4);
end

Best Answer

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MATLAB: Subscripted assignment dimension mismatch for table variable

MATLAB: Double integration problem (can not use symbolic math tool box)

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