Turn Ackermann function into a virtual stack [memory-compact version plus tail calls, shortened] [1030378]

< > BotCompany Repo | #1030378 // Turn Ackermann function into a virtual stack [memory-compact version plus tail calls, shortened]

JavaX source code (Dynamic Module) [tags: use-pretranspiled] - run with: Stefan's OS

cprint {
  sclass f_ackermann implements VStack.Computable<BigInt> {
    BigInt a, b;
    int currentStep; // 0 in the beginning, goes up to 1

    *(BigInt *a, BigInt *b) {}
    
    void step(VStack stack, O subComputationResult) {
      if (currentStep == 0) {
        if (a.equals(BigInt.ZERO))
          stack._return(plus(b, BigInt.ONE));
        else if (b.equals(BigInt.ZERO))
          stack.tailCall(new f_ackermann(a.subtract(BigInt.ONE), BigInt.ONE);
        else {
          stack.push(new f_ackermann(a, minus(b, BigInt.ONE)));
          currentStep = 1;
        }
      } else if (currentStep == 1)
        stack.tailCall(new f_ackermann(minus(a, BigInt.ONE), subComputationResult/BigInt));
      else fail();
    }
  }
  
  start-thread {
    print("Result: " + vStackComputeWithStats(new f_ackermann(bigInt(2), bigInt(2))));
  }
}

Author comment

Began life as a copy of #1030375

Travelled to 4 computer(s): bhatertpkbcr, mqqgnosmbjvj, pyentgdyhuwx, vouqrxazstgt

Snippet ID:

#1030378

Snippet name:

Turn Ackermann function into a virtual stack [memory-compact version plus tail calls, shortened]

Eternal ID of this version:

#1030378/3

Text MD5:

0a9acb1aa8265df8328984ee713acedb

Transpilation MD5:

d94c96a5f578d3286a3cc2c8a86f6e9d

Author:

stefan

Category:

javax / maths

Type:

JavaX source code (Dynamic Module)

Public (visible to everyone):

Yes

Archived (hidden from active list):

Created/modified:

2020-12-10 14:15:52

Source code size:

873 bytes / 27 lines

Pitched / IR pitched:

No / No

Views / Downloads:

192 / 279

Version history:

2 change(s)

Referenced in:

[show references]

1	cprint {
2	sclass f_ackermann implements VStack.Computable<BigInt> {
3	BigInt a, b;
4	int currentStep; // 0 in the beginning, goes up to 1
5
6	(BigInt a, BigInt *b) {}
7
8	void step(VStack stack, O subComputationResult) {
9	if (currentStep == 0) {
10	if (a.equals(BigInt.ZERO))
11	stack._return(plus(b, BigInt.ONE));
12	else if (b.equals(BigInt.ZERO))
13	stack.tailCall(new f_ackermann(a.subtract(BigInt.ONE), BigInt.ONE);
14	else {
15	stack.push(new f_ackermann(a, minus(b, BigInt.ONE)));
16	currentStep = 1;
17	}
18	} else if (currentStep == 1)
19	stack.tailCall(new f_ackermann(minus(a, BigInt.ONE), subComputationResult/BigInt));
20	else fail();
21	}
22	}
23
24	start-thread {
25	print("Result: " + vStackComputeWithStats(new f_ackermann(bigInt(2), bigInt(2))));
26	}
27	}