Java Reference
In-Depth Information
where
x
is the number whose logarithm you want,
n
is any desired base, and
e
is the natural
logarithm base. I have a simple
LogBase
class containing code that implements this function-
ality:
// LogBase.java
public
public static
static
double
double
log_base
(
double
double
base
,
double
double
value
) {
return
return
Math
.
log
(
value
) /
Math
.
log
(
base
);
}
Discussion
My
log_base
function allows you to compute logs to any positive base. If you have to per-
form a lot of logs to the same base, it is more efficient to rewrite the code to cache the
log(base)
once. Here is an example of using
log_base
:
// LogBaseUse.java
public static void main(String argv[]) {
double d = LogBase.log_base(10, 10000);
System.out.println("log10(10000) = " + d);
}
C:>
java numbers.LogBaseUse
log10(10000) = 4.0
Multiplying Matrices
Problem
You need to multiply a pair of two-dimensional arrays, as is common in mathematical and
engineering applications.
