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add logn and error checking for invalue eps and epsilon values

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Add new logn(x, n [,eps]) builtin to compute logarithms to base n.

Verify that eps arguments (error tolerance arguments that override
the default epsilon value) to builtin functions have proper values.
Previously the eps argument had little to no value checks for
many builtin functions.

Document in help files for builtin functions that take eps arguments,
the LIMIT range for such eps values.
This commit is contained in:
Landon Curt Noll
2023-08-31 22:33:41 -07:00
parent 4787199462
commit 1c839dfede
55 changed files with 1092 additions and 199 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
qtrans.c
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@@ -49,6 +49,8 @@ STATIC NUMBER *ln_10 = NULL;
STATIC NUMBER *ln_10_epsilon = NULL;
STATIC NUMBER *ln_2 = NULL;
STATIC NUMBER *ln_2_epsilon = NULL;
STATIC NUMBER *ln_n = NULL;
STATIC NUMBER *ln_n_epsilon = NULL;
/*
* cache pi
@@ -1049,10 +1051,14 @@ qln(NUMBER *q, NUMBER *epsilon)
NUMBER *qtmp, *res;
bool neg;
if (qiszero(q) || qiszero(epsilon)) {
if (qiszero(q)) {
math_error("logarithm of 0");
not_reached();
}
if (qiszero(epsilon)) {
math_error("Zero epsilon value for ln");
not_reached();
}
if (qisunit(q))
return qlink(&_qzero_);
q = qqabs(q); /* Ignore sign of q */
@@ -1161,10 +1167,14 @@ qlog(NUMBER *q, NUMBER *epsilon)
NUMBER *ret; /* base 10 logarithm of x */
/* firewall */
if (qiszero(q) || qiszero(epsilon)) {
if (qiszero(q)) {
math_error("logarithm of 0");
not_reached();
}
if (qiszero(epsilon)) {
math_error("Zero epsilon value for log");
not_reached();
}
/*
* shortcut for small integer powers of 10
@@ -1238,10 +1248,14 @@ qlog2(NUMBER *q, NUMBER *epsilon)
NUMBER *ret; /* base 2 logarithm of x */
/* firewall */
if (qiszero(q) || qiszero(epsilon)) {
if (qiszero(q)) {
math_error("logarithm of 0");
not_reached();
}
if (qiszero(epsilon)) {
math_error("Zero epsilon value for log2");
not_reached();
}
/*
* special case: q is integer power of 2
@@ -1256,7 +1270,7 @@ qlog2(NUMBER *q, NUMBER *epsilon)
* compute ln(c) first
*/
ln_q = qln(q, epsilon);
/* quick return for log(1) == 0 */
/* quick return for ln(1) == 0 */
if (qiszero(ln_q)) {
return ln_q;
}
@@ -1295,6 +1309,89 @@ qlog2(NUMBER *q, NUMBER *epsilon)
}
/*
* Calculate the base n logarithm
*
* logn(q, n) = ln(q) / ln(n)
*/
NUMBER *
qlogn(NUMBER *q, NUMBER *n, NUMBER *epsilon)
{
int need_new_ln_n = true; /* false => use cached ln_n value */
NUMBER *ln_q; /* ln(x) */
NUMBER *ret; /* base 2 logarithm of x */
/* firewall */
if (qiszero(q)) {
math_error("logarithm of 0");
not_reached();
}
if (qiszero(epsilon)) {
math_error("Zero epsilon value for logn");
not_reached();
}
if (qiszero(n)) {
math_error("invalid logarithm base of 0 for logn");
not_reached();
}
if (qisone(n)) {
math_error("invalid logarithm base of 1 for logn");
not_reached();
}
/*
* special case: q is integer power of 2
*/
ret = qalloc();
if (qispowerof2(q, &ret)) {
return ret;
}
/* XXX - deal with n is integer power of 2 - XXX */
qfree(ret);
/*
* compute ln(q) first
*/
ln_q = qln(q, epsilon);
/* quick return for ln(1) == 0 */
if (qiszero(ln_q)) {
return ln_q;
}
/*
* save epsilon for ln(n) if needed
*/
if (ln_n_epsilon == NULL) {
/* first time call */
ln_n_epsilon = qcopy(epsilon);
} else if (qcmp(ln_n_epsilon, epsilon) == true) {
/* replaced cached value with epsilon arg */
qfree(ln_n_epsilon);
ln_n_epsilon = qcopy(epsilon);
} else if (ln_n != NULL) {
/* the previously computed ln(2) is OK to use */
need_new_ln_n = false;
}
/*
* compute ln(n) if needed
*/
if (need_new_ln_n == true) {
if (ln_n != NULL) {
qfree(ln_n);
}
ln_n = qln(&_qtwo_, ln_n_epsilon);
}
/*
* return ln(q) / ln(2)
*/
ret = qqdiv(ln_q, ln_n);
qfree(ln_q);
return ret;
}
/*
* Calculate the result of raising one number to the power of another.
* The result is calculated to the nearest or next to nearest multiple of