Bio.mathfns

Package Bio :: Module mathfns

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Module Bio.mathfns

This provides useful general math tools.

Functions: fcmp Compare two floating point numbers, up to a specified precision. intd Represent a floating point number as an integer. safe_log log, but returns an arbitrarily small number for log(0). safe_exp exp, but returns a large or small number instead of overflows.

Function Summary
	`fcmp(x, y, precision)` fcmp(x, y, precision) -> -1, 0, or 1
	`intd(x, digits_after_decimal)` intd(x[, digits_after_decimal]) -> int x, rounded
	`safe_exp(n, under, over)` safe_exp(n, under=None, over=None) -> e**n
	`safe_log(n, zero, neg)` safe_log(n, zero=None, neg=None) -> log(n)
	`safe_log2(n, zero, neg)` safe_log2(n, zero=None, neg=None) -> log(n)

Variable Summary
`float`	`LOG2` = 0.69314718055994529

Function Details

fcmp(x, y, precision)

fcmp(x, y, precision) -> -1, 0, or 1

intd(x, digits_after_decimal=0)

intd(x[, digits_after_decimal]) -> int x, rounded

Represent a floating point number with some digits after the decimal point as an integer. This is useful when floating point comparisons are failing due to precision problems. e.g. intd(5.35, 1) -> 54.

safe_exp(n, under=None, over=None)

safe_exp(n, under=None, over=None) -> e**n

Guaranteed not to overflow. Instead of overflowing, it returns the values of 'under' for underflows or 'over' for overflows.

safe_log(n, zero=None, neg=None)

safe_log(n, zero=None, neg=None) -> log(n)

Calculate the log of n. If n is 0, returns the value of zero. If n is negative, returns the value of neg.

safe_log2(n, zero=None, neg=None)

safe_log2(n, zero=None, neg=None) -> log(n)

Calculate the log base 2 of n. If n is 0, returns the value of zero. If n is negative, returns the value of neg.

Variable Details

LOG2

Type:: float
Value:: 0.69314718055994529

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