PROCEDURE ReadAllChains(
    chainDir: TEXT;
    chainPrefix : TEXT;
    nCurves, band: NAT;
  ): ChainSetData =
  VAR sigma: LONG := -1.0d0;
  BEGIN
    WITH
      chainR = NEW(REF Chains, nCurves), chain = chainR^,
      sel = PZProc.SelectAll(nCurves)^,
      data = PZSymbolChain.ReadAll(
        prefix := chainPrefix, band := band, extension := ".cvc",
        sel := sel, dir := chainDir
      )
    DO
      FOR i := 0 TO LAST(sel) DO
        IF sel[i] THEN 
          WITH di = data[i] DO
            chain[i] := di.c;
            <* ASSERT di.sigma > 0.0d0 *>
            IF sigma < 0.0d0 THEN 
              sigma := di.sigma
            ELSE
              <* ASSERT sigma = di.sigma *>
            END
          END
        END
      END;
      RETURN ChainSetData{ chain := chainR, sigma := sigma }
    END;
  END ReadAllChains;



PROCEDURE RangesOverlap(i1, f1, i2, f2: CARDINAL; <*UNUSED*> m: CARDINAL): BOOLEAN =
  (*
    TRUE iff the intervals "[i1..f1]" and "[i2..f2]" overlap.
    Takes into account the fact that both intervals have been 
    reduced modulo "m".
  *)
  VAR ir, fr: CARDINAL;
  BEGIN
    RETURN PZProc.IntersectIntervals(i1, f1, i2, f2, (*OUT*) ir, fr)
  END RangesOverlap;

  




        IF pp.keywordPresent("-fractality") THEN
          o.fractality := pp.getNextLongReal(0.5d0, 2.0d0)
        ELSE
          o.fractality := 1.0d0
        END;
        


PROCEDURE ReduceSampleIndex(x: LONGREAL; m: CARDINAL): LONGREAL =
  (*
    Reduces the sample index "x" modulo the sample count "m". *)
  BEGIN
    WITH
      fm = FLOAT(m, LONGREAL)
    DO
      WHILE x < 0.0d0 DO x := x + fm END;
      WHILE x >= fm DO x := x - fm END;
      RETURN x
    END
  END ReduceSampleIndex;




PROCEDURE SymbolDist(a, b: PZSymbol.T; minCurvature: LONGREAL): LONGREAL =
  BEGIN 
    WITH
      va = FLOAT(+PZSymbol.ToInt(a), LONGREAL),
      vb = FLOAT(-PZSymbol.ToInt(b), LONGREAL),
      
      pa = MAX(0.0d0, minCurvature - ABS(va)),
      pb = MAX(0.0d0, minCurvature - ABS(vb))
    DO
      RETURN ABS(va - vb) + pa + pb
    END;  
  END SymbolDist;



PROCEDURE ComputeMeanStepLength(
    READONLY chain: ARRAY OF PZSymbolChain.ReadData;
  ): LONGREAL =
  BEGIN
    RETURN chain[0].length / FLOAT(chain[0].samples, LONGREAl)
  END ComputeMeanStepLength;

PROCEDURE GetNumSamples(READONLY chain: ARRAY OF REF PZSymbolChain.T): REF ARRAY OF CARDINAL =
  BEGIN
    WITH 
      nCurves = NUMBER(chain),
      m = NEW(REF ARRAY OF CARDINAL, nCurves)
    DO 
      FOR i := 0 TO nCurves-1 DO 
        m[i] := NUMBER(chain[i]^)
      END;
      RETURN m
    END
  END GetNumSamples;
  

          Wr.PutText(stderr, "\n" & Fmt.Int(ia) & ".." & Fmt.Int(k MOD ma));
          Wr.PutText(stderr, " count = " & Fmt.Int(count));