FDS (KR) - Ass 2 (Matrix Operations)

##################
###  MATRICES  ###
##################

# Function for Initializing a Matrix
def initMatrix():
    rows = int(input("Enter the number of Rows: "))
    cols = int(input("Enter the number of Columns: "))
    matrix = []
    for i in range(0, rows):
        row = []
        for j in range(0, cols):
            element = int(input("Enter the element at position (" + str(i) + ", " + str(j) + "): "))
            row.append(element)
        matrix.append(row)
    return matrix


# Function for Displaying a Matrix
def displayMatrix(matrix):
        for i in range(0,len(matrix)):
            print()
            for j in range(0, len(matrix[0])):
                print(str(matrix[i][j]).rjust(2), end = " ")
        print()
        print()


# Function for Adding two Matrices
def add(matrixA, matrixB):
    sum_matrix = []
    if ( (len(matrixA) == len(matrixB)) and (len(matrixA[0]) == len(matrixB[0])) ):
        for i in range(0, len(matrixA)):
            row_sums = []
            for j in range(0, len(matrixA[0])):
                row_sums.append((matrixA[i][j] + matrixB[i][j]))
            sum_matrix.append(row_sums)
        return sum_matrix
    else:
        print("ERROR! The Matrix Dimensions DO NOT MATCH")
        return -1


# Function for Subtracting two Matrices
def subtract(matrixA, matrixB):
    sum_matrix = []
    if ( (len(matrixA) == len(matrixB)) and (len(matrixA[0]) == len(matrixB[0])) ):
        for i in range(0, len(matrixA)):
            row_sums = []
            for j in range(0, len(matrixA[0])):
                row_sums.append((matrixA[i][j] - matrixB[i][j]))
            sum_matrix.append(row_sums)
        return sum_matrix
    else:
        print("ERROR! The Matrix Dimensions DO NOT MATCH")
        return -1


# Function for Initializing a Null Matrix with Given Dimensions
def initNull(rows, cols):
    null_matrix = []
    for i in range(rows):
        null_row = []
        for j in range(cols):
            null_row.append(0)
        null_matrix.append(null_row)
    return null_matrix


# Function for Multiplying two Matrices
def multiply(mA, mB):
    if (len(mA[0]) == len(mB)):
        result = initNull(len(mA[0]), len(mB))
        prod_matrix = []
        for i in range(0, len(mA)):
            row_prods = []
            for j in range(0, len(mB[0])):
                term = 0
                for k in range(0, len(mA[0])):
                    term += mA[i][k] * mB[k][j]
                result[i][j] = term
        return result
#         ???
#         for i in range(0, range(len(mA))):
#             row_prods = []
#             for j in range(0, range(len(mA[0]))):
#                 element = (mA[i][j] * mB[j][i])
    else:
        print("ERROR! Invalid Dimensions")
        return -1


# Function of obtaining Transpose of a Matrix
def transpose(mA):
    ok = mA
    null_matrix = initNull(len(mA), len(mA[0]))
    for i in range(len(mA)):
        for j in range (len(mA[0])):
             null_matrix[j][i] = mA[i][j]
    return null_matrix



print("Initializing Matrices")
A = initMatrix()
B = initMatrix()
# displayMatrix(A)
# displayMatrix(B)

print("Addition: ")
Sum = add(A, B)
displayMatrix(Sum)

print("Subtraction: ")
Difference = subtract(A, B)
displayMatrix(Difference)

print("Multiplication: ")
Multiplication = multiply(A, B)
displayMatrix(Multiplication)

print("Transpose: ")
Transposed = transpose(A)
displayMatrix(Transposed)