LOZAN@TAUNOS.BITNET (12/28/89)
SYMBOLIC MATRICES ----------------- This is a set of programs which handle symbolic matrices for the hP28s. The matrices are entered as a list, for example {{A B }{ C D }}. This package contains programs for determinant,inverse of matrices,eigen values, multiplication of matrices & multiplication by a scalar. Bugs: The eigenvalue program works only if the values are all real. In this text '<>' means not equal. det [9463] (Lowercase are important !!) << DUP SIZE -> A B << IF B 1 == ; det of a 1x1 matrix THEN A 1 GET ELSE IF B 2 == THEN A DET2 ; call basic case of 2x2 determinant ELSE 0 1 B FOR I A 1 GET I GET A 1 MINOR det ; recursive call * -1 1 I + ^ * + NEXT END END >> >> DET2 [4853] ; This is an accessory program to compute A*D-B*C ; from {{A B}{C D}} << -> A << A 1 GET 1 GET A 2 GET 2 GET * A 1 GET 2 GET A 2 GET 1 GET * - >> >> MINOR [33F1] ; This is also an accessory program to compute M(i,j) of ; an element in the matrix << -> A B C << A SIZE -> S << 1 S FOR I IF B I <> THEN A I GET -> D << 1 S FOR J IF J C <> THEN D J GET END NEXT S 1 - ->LIST >> END NEXT S 1 - ->LIST >> >> >> inv [9F8A] ; Compute the inverse of the matrix in level 1. ; The output is 2: B (a matrix) ; 1: C (an algebraic expression) ; where inv(A) = B / C . ; This program use the cramer rule to compute the inverse. << DUP SIZE -> A B << 1 B FOR I 1 B FOR J A J I MINOR det -1 I J + ^ * NEXT B ->LIST NEXT B ->LIST A det >> >> MMUL [866C] ; matrices multiplication ; input 2: A ; 1: B ; output 1: A*B << -> A B << A SIZE B SIZE B 1 GET SIZE -> L C R << 1 L FOR I A I GET -> LI << 1 R FOR J 0 1 C FOR K LI K GET B K GET J GET * + NEXT NEXT R ->LIST >> NEXT L ->LIST >> >> >> SCMUL [76CB] ; scalar multiplication program ; input 2: scalar ; 1: matrix ; output 1: matrix = scalar * matrix << DUP SIZE -> M A S << 1 S FOR A I GET -> C << 1 S FOR J C J GET M * NEXT >> S ->LIST NEXT S ->LIST >> >> DIVP [B8B7] ; eliminate one real root from polynom ; input 3: a polynom in S [P(S)] ; 2: the degree of this polynom ; 1: the root we want to eliminate [a] ; output 1: P(S)/(S-a) << -> P Q R << P 'S' R - / 'S' K 1 - TAYLR >> >> eigf [D819] ; This program returns the eigen function of a given matrix << DUP SIZE -> A B << B '-S' SIDN A add det >> >> add [9B5A] ; sum of two matrices ; input 2: A (matrix) ; 1: B (matrix) ; output 1: A + B << DUP SIZE -> B A S << 1 S FOR I A I GET B I GET -> C D << 1 S FOR J C J GET D J GET + NEXT >> S ->LIST NEXT S ->LIST >> >> SIDN [539F] ; This program return an identity matrix multiplied by a scalar ; input 1: size (scalar) ; 2: const (algbraic object) ; output 1: const * I << -> K S << 1 K FOR I 1 K FOR J I J == S * NEXT K ->LIST NEXT K ->LIST >> >> EIGV [A4D6] ; returns the eigenvalues of a matrix << -> A << A eigf STEQ A SIZE 1 FOR I RCEQ 'S' 0 ROOT RCEQ I 3 PICK DIVP STEQ -1 STEP { S EQ } PURGE >> >> The result of some program may produce large expression as element of matrices. So if somone isn't very interested in speed he can place COLCT commands in strategic places, but this will slow down the computing drastictly. If you have any comments,improvments or if you find typing mistakes in this text ,please contact me. ------------------------------------------------------------------------------ Eliel Louzoun < LOZAN@TAUNOS >.