MIN(3) 1 MIN(3)
min - Find lowest value
SYNOPSIS
mixed min (array $values)
DESCRIPTION
mixed min (mixed $value1, mixed $value2, [mixed $...])
If the first and only parameter is an array, min(3) returns the lowest value in that array. If at least two parameters are provided,
min(3) returns the smallest of these values.
Note
Values of different types will be compared using the standard comparison rules. For instance, a non-numeric string will be com-
pared to an integer as though it were 0, but multiple string values will be compared alphanumerically. The actual value returned
will be of the original type with no conversion applied.
PARAMETERS
o $values
- An array containing the values.
o $value1
- Any comparable value.
o $value2
- Any comparable value.
o $...
- Any comparable value.
RETURN VALUES
min(3) returns the parameter value considered "lowest" according to standard comparisons. If multiple values of different types evaluate as
equal (e.g. 0 and 'abc') the first provided to the function will be returned.
EXAMPLES
Example #1
Example uses of min(3)
<?php
echo min(2, 3, 1, 6, 7); // 1
echo min(array(2, 4, 5)); // 2
// The string 'hello' when compared to an int is treated as 0
// Since the two values are equal, the order they are provided determines the result
echo min(0, 'hello'); // 0
echo min('hello', 0); // hello
// Here we are comparing -1 < 0, so -1 is the lowest value
echo min('hello', -1); // -1
// With multiple arrays of different lengths, min returns the shortest
$val = min(array(2, 2, 2), array(1, 1, 1, 1)); // array(2, 2, 2)
// Multiple arrays of the same length are compared from left to right
// so in our example: 2 == 2, but 4 < 5
$val = min(array(2, 4, 8), array(2, 5, 1)); // array(2, 4, 8)
// If both an array and non-array are given, the array is never returned
// as comparisons treat arrays as greater than any other value
$val = min('string', array(2, 5, 7), 42); // string
// If one argument is NULL or a boolean, it will be compared against
// other values using the rule FALSE < TRUE regardless of the other types involved
// In the below examples, both -10 and 10 are treated as TRUE in the comparison
$val = min(-10, FALSE, 10); // FALSE
$val = min(-10, NULL, 10); // NULL
// 0, on the other hand, is treated as FALSE, so is "lower than" TRUE
$val = min(0, TRUE); // 0
?>
SEE ALSO
max(3), count(3).
PHP Documentation Group MIN(3)
Check Out this Related Man Page
SGESDD(l) ) SGESDD(l)
NAME
SGESDD - compute the singular value decomposition (SVD) of a real M-by-N matrix A, optionally computing the left and right singular vectors
SYNOPSIS
SUBROUTINE SGESDD( JOBZ, M, N, A, LDA, S, U, LDU, VT, LDVT, WORK, LWORK, IWORK, INFO )
CHARACTER JOBZ
INTEGER INFO, LDA, LDU, LDVT, LWORK, M, N
INTEGER IWORK( * )
REAL A( LDA, * ), S( * ), U( LDU, * ), VT( LDVT, * ), WORK( * )
PURPOSE
SGESDD computes the singular value decomposition (SVD) of a real M-by-N matrix A, optionally computing the left and right singular vectors.
If singular vectors are desired, it uses a divide-and-conquer algorithm.
The SVD is written
A = U * SIGMA * transpose(V)
where SIGMA is an M-by-N matrix which is zero except for its min(m,n) diagonal elements, U is an M-by-M orthogonal matrix, and V is an N-
by-N orthogonal matrix. The diagonal elements of SIGMA are the singular values of A; they are real and non-negative, and are returned in
descending order. The first min(m,n) columns of U and V are the left and right singular vectors of A.
Note that the routine returns VT = V**T, not V.
The divide and conquer algorithm makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit
in add/subtract, or on those binary machines without guard digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or Cray-2. It
could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none.
ARGUMENTS
JOBZ (input) CHARACTER*1
Specifies options for computing all or part of the matrix U:
= 'A': all M columns of U and all N rows of V**T are returned in the arrays U and VT; = 'S': the first min(M,N) columns of U and
the first min(M,N) rows of V**T are returned in the arrays U and VT; = 'O': If M >= N, the first N columns of U are overwritten on
the array A and all rows of V**T are returned in the array VT; otherwise, all columns of U are returned in the array U and the
first M rows of V**T are overwritten in the array VT; = 'N': no columns of U or rows of V**T are computed.
M (input) INTEGER
The number of rows of the input matrix A. M >= 0.
N (input) INTEGER
The number of columns of the input matrix A. N >= 0.
A (input/output) REAL array, dimension (LDA,N)
On entry, the M-by-N matrix A. On exit, if JOBZ = 'O', A is overwritten with the first N columns of U (the left singular vectors,
stored columnwise) if M >= N; A is overwritten with the first M rows of V**T (the right singular vectors, stored rowwise) other-
wise. if JOBZ .ne. 'O', the contents of A are destroyed.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,M).
S (output) REAL array, dimension (min(M,N))
The singular values of A, sorted so that S(i) >= S(i+1).
U (output) REAL array, dimension (LDU,UCOL)
UCOL = M if JOBZ = 'A' or JOBZ = 'O' and M < N; UCOL = min(M,N) if JOBZ = 'S'. If JOBZ = 'A' or JOBZ = 'O' and M < N, U contains
the M-by-M orthogonal matrix U; if JOBZ = 'S', U contains the first min(M,N) columns of U (the left singular vectors, stored colum-
nwise); if JOBZ = 'O' and M >= N, or JOBZ = 'N', U is not referenced.
LDU (input) INTEGER
The leading dimension of the array U. LDU >= 1; if JOBZ = 'S' or 'A' or JOBZ = 'O' and M < N, LDU >= M.
VT (output) REAL array, dimension (LDVT,N)
If JOBZ = 'A' or JOBZ = 'O' and M >= N, VT contains the N-by-N orthogonal matrix V**T; if JOBZ = 'S', VT contains the first
min(M,N) rows of V**T (the right singular vectors, stored rowwise); if JOBZ = 'O' and M < N, or JOBZ = 'N', VT is not referenced.
LDVT (input) INTEGER
The leading dimension of the array VT. LDVT >= 1; if JOBZ = 'A' or JOBZ = 'O' and M >= N, LDVT >= N; if JOBZ = 'S', LDVT >=
min(M,N).
WORK (workspace/output) REAL array, dimension (LWORK)
On exit, if INFO = 0, WORK(1) returns the optimal LWORK;
LWORK (input) INTEGER
The dimension of the array WORK. LWORK >= 1. If JOBZ = 'N', LWORK >= 3*min(M,N) + max(max(M,N),6*min(M,N)). If JOBZ = 'O', LWORK
>= 3*min(M,N)*min(M,N) + max(max(M,N),5*min(M,N)*min(M,N)+4*min(M,N)). If JOBZ = 'S' or 'A' LWORK >= 3*min(M,N)*min(M,N) +
max(max(M,N),4*min(M,N)*min(M,N)+4*min(M,N)). For good performance, LWORK should generally be larger. If LWORK < 0 but other
input arguments are legal, WORK(1) returns the optimal LWORK.
IWORK (workspace) INTEGER array, dimension (8*min(M,N))
INFO (output) INTEGER
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
> 0: SBDSDC did not converge, updating process failed.
FURTHER DETAILS
Based on contributions by
Ming Gu and Huan Ren, Computer Science Division, University of
California at Berkeley, USA
LAPACK version 3.0 15 June 2000 SGESDD(l)