how to solve an equation of the form ax=b

how to solve an equation of the form ax=b where a has dimension 1024*1023 and x has dimension 1023*1?i have used pinv command.but when i multiplied the result with a,i didnt get the same b matrix

Answer 1

[Stephen23]

Use mldivide: "Solve systems of linear equations Ax = B for x"

Answer 2

[Torsten]

If you have 1024 equations for 1023 variables, the system can in general not be solved exactly.

What you get by typing

x=a\b

is an optimal solution in the least-squares sense, i.e. a solution that minimizes the error

||a*x-b||_2-Norm

Best wishes

Torsten.