storing high-precision data in a matrix will store double type data by default.
The data type of an array is determined by the first value you store to the array.
If you initialize the array
M = zeros(10,10);
then that creates M as a double precision array, and if you attempt to store a symbolic number into part of M, then the symbolic number will be converted to double precision.
So instead initialize the array as symbolic:
M = zeros(10, 10, 'sym');
After which, for example,
M(1,1) = vpa(exp(sym(pi)),200);
Note that the full 200 digits will not be displayed, but you can tell with calculations that they are stored internally.
