This member function changes the value of the invoking function on the interval [x1,x2). On this interval, the invoking function is set to equal a repetition of the pattern function f with an initial offset of offset. The invoking function is not modified outside the interval [x1,x2). More precisely, if [min,max) denotes the definition interval of f, for all t in [x1,x2), the invoking function at t is set to equal f(min + (offset+t-x1)%(max-min))) where % denotes the modulo operator. By default, the offset is equal to 0.