package main

type Matrix []Vector

func MakeMatrix(n, m int) Matrix {
	M := make(Matrix, n)
	for i := 0; i < n; i++ {
		M[i] = MakeVector(m)
	}
	return M
}

func MakeRandomMatrix(n, m int) Matrix {
	M := make(Matrix, n)
	for i := 0; i < n; i++ {
		M[i] = MakeRandomVector(m)
	}
	return M
}

func (A Matrix) N() int {
	return len(A)
}

func (A Matrix) M() int {
	return A[0].N()
}

func (A Matrix) Transpose() Matrix {
	B := MakeMatrix(A.M(), A.N())
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			B[j][i] = A[i][j]
		}
	}
	return B
}

func (A Matrix) Add(B Matrix) Matrix {
	if A.N() != B.N() || A.M() != B.M() {
		panic("Incompatible Dimensions")
	}
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			A[i][j] += B[i][j]
		}
	}
	return A
}

func (A Matrix) Sub(B Matrix) Matrix {
	if A.N() != B.N() || A.M() != B.M() {
		panic("Incompatible Dimensions")
	}
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			A[i][j] -= B[i][j]
		}
	}
	return A
}

func (A Matrix) Multiply(B Matrix) Matrix {
	if A.M() != B.N() {
		panic("Incompatible Dimensions")
	}
	C := MakeMatrix(A.N(), B.M())
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			if A[i][j] != 0 {
				for k := 0; k < B.M(); k++ {
					if B[j][k] != 0 {
						C[i][k] += A[i][j] * B[j][k]
					}
				}
			}
		}
	}
	return C
}

func (A Matrix) Divide(b float64) Matrix {
	if b == 1 {
		return A
	}
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			A[i][j] /= b
		}
	}
	return A
}

func (A Matrix) Dropout(B Vector) Matrix {
	if A.M() != B.N() {
		panic("Incompatible Dimensions")
	}
	for i := 0; i < A.N(); i++ {
		for j := 0; j < A.M(); j++ {
			A[i][j] *= B[j]
		}
	}
	return A
}