Force the separator for decimal point to be a dot. See https://github.com/piwik/piwik/issues/6435
If for instance a German locale is used it would be a comma otherwise.
This example shows how to sanitize an input value that uses a comma (,) as the decimal point separator and then format it using the forceDotAsSeparatorForDecimalPoint function. The Common forceDotAsSeparatorForDecimalPoint function belongs to the Piwik Common library.