# solve: Solve methods for 'DMat', 'ShrnkMat', 'ShrnkMatInv', 'SigFq'... In HiDimDA: High Dimensional Discriminant Analysis

## Description

These methods solve the equation `a %*% x = b` for ‘x’, where ‘a’ is a specialized square symmetric matrix represented by a ‘DMat’, ‘ShrnkMat’, ‘ShrnkMatInv’, ‘SigFq’ or ‘SigFqInv’ object, and ‘b’ can be either a vector or a matrix.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10``` ```## S3 method for class 'DMat' solve(a, b = NULL, ...) ## S3 method for class 'ShrnkMat' solve(a, b = NULL, ...) ## S3 method for class 'ShrnkMatInv' solve(a, b = NULL, ...) ## S3 method for class 'SigFq' solve(a, b = NULL, ...) ## S3 method for class 'SigFqInv' solve(a, b = NULL, ...) ```

## Arguments

 `a` An object of type ‘DMat’, ‘ShrnkMat’, ‘ShrnkMatInv’, ‘SigFq’ or ‘SigFqInv’ representing a specialized symmetric square matrix. `b` A numeric vector or matrix giving the right-hand side(s) of the linear system. If missing, ‘b’ is taken to be an identity matrix and solve will return an object representing the inverse of the matrix associated with ‘a’. `...` Further arguments passed to or from other methods.

## Details

The result returned depends on the values of the arguments. When ‘b’ is not NULL, both functions return a numeric vector or matrix with the solution of the system. When ‘b’ is NULL, ‘solve.DMat’ returns a ‘DMat’ object, ‘solve.ShrnkMat’ a ‘ShrnkMatInv’ object, ‘solve.ShrnkMatInv’ a ‘ShrnkMat’ object, ‘solve.SigFq’ a ‘SigFqInv’ object and ‘solve.SigFqInv’ returns a ‘SigFq’ object.

`DMat`, `ShrnkMat`, `ShrnkMatInv`, `SigFq`, `SigFqInv`, `FrobSigAp`, `solve`