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17.1 Exponents and Logarithms

Mapping Function: exp (x)

Compute e^x for each element of x. To compute the matrix exponential, see Linear Algebra.

See also: log.

Mapping Function: expm1 (x)

Compute exp (x) - 1 accurately in the neighborhood of zero.

See also: exp.

Mapping Function: log (x)

Compute the natural logarithm, ln (x), for each element of x. To compute the matrix logarithm, see Linear Algebra.

See also: exp, log1p, log2, log10, logspace.

Mapping Function: log1p (x)

Compute log (1 + x) accurately in the neighborhood of zero.

See also: log, exp, expm1.

Mapping Function: log10 (x)

Compute the base-10 logarithm of each element of x.

See also: log, log2, logspace, exp.

Mapping Function: log2 (x)

Mapping Function: [f, e] = log2 (x)

Compute the base-2 logarithm of each element of x.

If called with two output arguments, split x into binary mantissa and exponent so that 1/2 <= abs(f) < 1 and e is an integer. If x = 0, f = e = 0.

See also: pow2, log, log10, exp.

Function File: nextpow2 (x)

If x is a scalar, return the first integer n such that 2^n >= abs (x).

If x is a vector, return nextpow2 (length (x)).

See also: pow2, log2.

Function File: nthroot (x, n)

Compute the n-th root of x, returning real results for real components of x. For example

nthroot (-1, 3)
⇒ -1
(-1) ^ (1 / 3)
⇒ 0.50000 - 0.86603i

Mapping Function: pow2 (x)

Mapping Function: pow2 (f, e)

With one argument, computes 2 .^ x for each element of x.

With two arguments, returns f .* (2 .^ e).

See also: log2, nextpow2.

Function File: reallog (x)

Return the real-valued natural logarithm of each element of x. Report an error if any element results in a complex return value.

See also: log, realpow, realsqrt.

Function File: realpow (x, y)

Compute the real-valued, element-by-element power operator. This is equivalent to x .^ y, except that realpow reports an error if any return value is complex.

See also: reallog, realsqrt.

Function File: realsqrt (x)

Return the real-valued square root of each element of x. Report an error if any element results in a complex return value.

See also: sqrt, realpow, reallog.

Mapping Function: sqrt (x)

Compute the square root of each element of x. If x is negative, a complex result is returned. To compute the matrix square root, see Linear Algebra.

See also: realsqrt.

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