NTL Memory Usage

From Upp

Sometimes it can be useful to estimate the amount of memory needed for basic NTL containers.

Here are some general formulas you can use, in each formula T stands for the template variable in use:

Contents 1 Vectors 2 Arrays 3 Index 4 VectorMap / ArrayMap

Vectors

Memory required = sizeof(T) * GetCount() * 1.33

In case the size of the template is dynamic, use the avarage. GetCount() is how many element are needed/used for the vector. And the expansion reserve is calculated by multiplying with 1.33.

Arrays

Memory required = sizeof(T) * GetCount() + (1.33 * sizeof(void *))

One should keep in mind that the elements are pointed to in an array, thus this container uses less memory.

Index

Memory required = sizeof(T) * GetCount() * 1.33 * Hash size

Index works almost the same as vectors, but adds a hash to each element. The hash size(StdHash<T>) is on average 20 bytes.

VectorMap / ArrayMap

Maps are basically the Index + Array / Vector.