plugins/renepay/dijkstra: improve API to remove global.

The global is an *internal* hack because dijkstra_item_mover doesn't
take a context arg!  It should be used with care.

Easy, since all the accessors exist: we just hand in the struct dijkstra.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2023-07-31 11:21:25 +09:30
parent 79486c1e3b
commit b5da85e85d
4 changed files with 155 additions and 167 deletions

View File

@@ -2,6 +2,22 @@
#include "config.h"
#include <plugins/renepay/dijkstra.h>
/* In the heap we keep node idx, but in this structure we keep the distance
* value associated to every node, and their position in the heap as a pointer
* so that we can update the nodes inside the heap when the distance label is
* changed.
*
* Therefore this is no longer a multipurpose heap, the node_idx must be an
* index between 0 and less than max_num_nodes. */
struct dijkstra {
//
s64 *distance;
u32 *base;
u32 **heapptr;
size_t heapsize;
struct gheap_ctx gheap_ctx;
};
static const s64 INFINITE = INT64_MAX;
/* Required a global dijkstra for gheap. */
@@ -29,146 +45,142 @@ static void dijkstra_item_mover(void *const dst, const void *const src)
global_dijkstra->heapptr[src_idx] = dst;
}
/* Destructor for global dijkstra. The valid free state is signalled with a
* NULL ptr. */
static void dijkstra_destroy(struct dijkstra *ptr UNUSED)
{
global_dijkstra=NULL;
}
/* Manually release dijkstra resources. */
void dijkstra_free(void)
{
if(global_dijkstra)
{
global_dijkstra = tal_free(global_dijkstra);
}
}
/* Allocation of resources for the heap. */
void dijkstra_malloc(const tal_t *ctx, const size_t max_num_nodes)
struct dijkstra *dijkstra_new(const tal_t *ctx, size_t max_num_nodes)
{
dijkstra_free();
struct dijkstra *dijkstra = tal(ctx, struct dijkstra);
global_dijkstra = tal(ctx,struct dijkstra);
tal_add_destructor(global_dijkstra,dijkstra_destroy);
dijkstra->distance = tal_arr(dijkstra,s64,max_num_nodes);
dijkstra->base = tal_arr(dijkstra,u32,max_num_nodes);
dijkstra->heapptr = tal_arrz(dijkstra,u32*,max_num_nodes);
global_dijkstra->distance = tal_arr(global_dijkstra,s64,max_num_nodes);
global_dijkstra->base = tal_arr(global_dijkstra,u32,max_num_nodes);
global_dijkstra->heapptr = tal_arrz(global_dijkstra,u32*,max_num_nodes);
dijkstra->heapsize=0;
global_dijkstra->heapsize=0;
dijkstra->gheap_ctx.fanout=2;
dijkstra->gheap_ctx.page_chunks=1024;
dijkstra->gheap_ctx.item_size=sizeof(dijkstra->base[0]);
dijkstra->gheap_ctx.less_comparer=dijkstra_less_comparer;
dijkstra->gheap_ctx.less_comparer_ctx=NULL;
dijkstra->gheap_ctx.item_mover=dijkstra_item_mover;
global_dijkstra->gheap_ctx.fanout=2;
global_dijkstra->gheap_ctx.page_chunks=1024;
global_dijkstra->gheap_ctx.item_size=sizeof(global_dijkstra->base[0]);
global_dijkstra->gheap_ctx.less_comparer=dijkstra_less_comparer;
global_dijkstra->gheap_ctx.less_comparer_ctx=NULL;
global_dijkstra->gheap_ctx.item_mover=dijkstra_item_mover;
return dijkstra;
}
void dijkstra_init(void)
void dijkstra_init(struct dijkstra *dijkstra)
{
const size_t max_num_nodes = tal_count(global_dijkstra->distance);
global_dijkstra->heapsize=0;
const size_t max_num_nodes = tal_count(dijkstra->distance);
dijkstra->heapsize=0;
for(size_t i=0;i<max_num_nodes;++i)
{
global_dijkstra->distance[i]=INFINITE;
global_dijkstra->heapptr[i] = NULL;
dijkstra->distance[i]=INFINITE;
dijkstra->heapptr[i] = NULL;
}
}
size_t dijkstra_size(void)
size_t dijkstra_size(const struct dijkstra *dijkstra)
{
return global_dijkstra->heapsize;
return dijkstra->heapsize;
}
size_t dijkstra_maxsize(void)
size_t dijkstra_maxsize(const struct dijkstra *dijkstra)
{
return tal_count(global_dijkstra->distance);
return tal_count(dijkstra->distance);
}
static void dijkstra_append(u32 node_idx, s64 distance)
static void dijkstra_append(struct dijkstra *dijkstra, u32 node_idx, s64 distance)
{
assert(dijkstra_size() < dijkstra_maxsize());
assert(node_idx < dijkstra_maxsize());
assert(dijkstra_size(dijkstra) < dijkstra_maxsize(dijkstra));
assert(node_idx < dijkstra_maxsize(dijkstra));
const size_t pos = global_dijkstra->heapsize;
const size_t pos = dijkstra->heapsize;
global_dijkstra->base[pos]=node_idx;
global_dijkstra->distance[node_idx]=distance;
global_dijkstra->heapptr[node_idx] = &(global_dijkstra->base[pos]);
global_dijkstra->heapsize++;
dijkstra->base[pos]=node_idx;
dijkstra->distance[node_idx]=distance;
dijkstra->heapptr[node_idx] = &(dijkstra->base[pos]);
dijkstra->heapsize++;
}
void dijkstra_update(u32 node_idx, s64 distance)
{
assert(node_idx < dijkstra_maxsize());
if(!global_dijkstra->heapptr[node_idx])
void dijkstra_update(struct dijkstra *dijkstra, u32 node_idx, s64 distance)
{
assert(node_idx < dijkstra_maxsize(dijkstra));
if(!dijkstra->heapptr[node_idx])
{
// not in the heap
dijkstra_append(node_idx,distance);
dijkstra_append(dijkstra, node_idx,distance);
global_dijkstra = dijkstra;
gheap_restore_heap_after_item_increase(
&global_dijkstra->gheap_ctx,
global_dijkstra->base,
global_dijkstra->heapsize,
global_dijkstra->heapptr[node_idx]
- global_dijkstra->base);
&dijkstra->gheap_ctx,
dijkstra->base,
dijkstra->heapsize,
dijkstra->heapptr[node_idx]
- dijkstra->base);
global_dijkstra = NULL;
return;
}
if(global_dijkstra->distance[node_idx] > distance)
if(dijkstra->distance[node_idx] > distance)
{
// distance decrease
global_dijkstra->distance[node_idx] = distance;
dijkstra->distance[node_idx] = distance;
global_dijkstra = dijkstra;
gheap_restore_heap_after_item_increase(
&global_dijkstra->gheap_ctx,
global_dijkstra->base,
global_dijkstra->heapsize,
global_dijkstra->heapptr[node_idx]
- global_dijkstra->base);
&dijkstra->gheap_ctx,
dijkstra->base,
dijkstra->heapsize,
dijkstra->heapptr[node_idx]
- dijkstra->base);
global_dijkstra = NULL;
}else
{
// distance increase
global_dijkstra->distance[node_idx] = distance;
dijkstra->distance[node_idx] = distance;
global_dijkstra = dijkstra;
gheap_restore_heap_after_item_decrease(
&global_dijkstra->gheap_ctx,
global_dijkstra->base,
global_dijkstra->heapsize,
global_dijkstra->heapptr[node_idx]
- global_dijkstra->base);
&dijkstra->gheap_ctx,
dijkstra->base,
dijkstra->heapsize,
dijkstra->heapptr[node_idx]
- dijkstra->base);
global_dijkstra = NULL;
}
// assert(gheap_is_heap(&global_dijkstra->gheap_ctx,
// global_dijkstra->base,
// assert(gheap_is_heap(&dijkstra->gheap_ctx,
// dijkstra->base,
// dijkstra_size()));
}
u32 dijkstra_top(void)
u32 dijkstra_top(const struct dijkstra *dijkstra)
{
return global_dijkstra->base[0];
return dijkstra->base[0];
}
bool dijkstra_empty(void)
bool dijkstra_empty(const struct dijkstra *dijkstra)
{
return global_dijkstra->heapsize==0;
return dijkstra->heapsize==0;
}
void dijkstra_pop(void)
void dijkstra_pop(struct dijkstra *dijkstra)
{
if(global_dijkstra->heapsize==0)
if(dijkstra->heapsize==0)
return;
const u32 top = dijkstra_top();
assert(global_dijkstra->heapptr[top]==global_dijkstra->base);
const u32 top = dijkstra_top(dijkstra);
assert(dijkstra->heapptr[top]==dijkstra->base);
global_dijkstra = dijkstra;
gheap_pop_heap(
&global_dijkstra->gheap_ctx,
global_dijkstra->base,
global_dijkstra->heapsize--);
&dijkstra->gheap_ctx,
dijkstra->base,
dijkstra->heapsize--);
global_dijkstra = NULL;
global_dijkstra->heapptr[top]=NULL;
dijkstra->heapptr[top]=NULL;
}
const s64* dijkstra_distance_data(void)
const s64* dijkstra_distance_data(const struct dijkstra *dijkstra)
{
return global_dijkstra->distance;
return dijkstra->distance;
}

View File

@@ -5,45 +5,26 @@
#include <ccan/tal/tal.h>
#include <gheap.h>
/* In the heap we keep node idx, but in this structure we keep the distance
* value associated to every node, and their position in the heap as a pointer
* so that we can update the nodes inside the heap when the distance label is
* changed.
*
* Therefore this is no longer a multipurpose heap, the node_idx must be an
* index between 0 and less than max_num_nodes. */
struct dijkstra {
//
s64 *distance;
u32 *base;
u32 **heapptr;
size_t heapsize;
struct gheap_ctx gheap_ctx;
};
/* Allocation of resources for the heap. */
void dijkstra_malloc(const tal_t *ctx, const size_t max_num_nodes);
/* Manually release dijkstra resources. */
void dijkstra_free(void);
struct dijkstra *dijkstra_new(const tal_t *ctx, size_t max_num_nodes);
/* Initialization of the heap for a new Dijkstra search. */
void dijkstra_init(void);
void dijkstra_init(struct dijkstra *dijkstra);
/* Inserts a new element in the heap. If node_idx was already in the heap then
* its distance value is updated. */
void dijkstra_update(u32 node_idx, s64 distance);
void dijkstra_update(struct dijkstra *dijkstra, u32 node_idx, s64 distance);
u32 dijkstra_top(void);
bool dijkstra_empty(void);
void dijkstra_pop(void);
u32 dijkstra_top(const struct dijkstra *dijkstra);
bool dijkstra_empty(const struct dijkstra *dijkstra);
void dijkstra_pop(struct dijkstra *dijkstra);
const s64* dijkstra_distance_data(void);
const s64* dijkstra_distance_data(const struct dijkstra *dijkstra);
/* Number of elements on the heap. */
size_t dijkstra_size(void);
size_t dijkstra_size(const struct dijkstra *dijkstra);
/* Maximum number of elements the heap can host */
size_t dijkstra_maxsize(void);
size_t dijkstra_maxsize(const struct dijkstra *dijkstra);
#endif /* LIGHTNING_PLUGINS_RENEPAY_DIJKSTRA_H */

View File

@@ -849,6 +849,7 @@ static int find_feasible_flow(
/* Similar to `find_admissible_path` but use Dijkstra to optimize the distance
* label. Stops when the target is hit. */
static int find_optimal_path(
struct dijkstra *dijkstra,
const struct linear_network *linear_network,
const struct residual_network* residual_network,
const u32 source,
@@ -864,15 +865,15 @@ static int find_optimal_path(
for(size_t i=0;i<tal_count(prev);++i)
prev[i].idx=INVALID_INDEX;
s64 const * const distance=dijkstra_distance_data();
s64 const * const distance=dijkstra_distance_data(dijkstra);
dijkstra_init();
dijkstra_update(source,0);
dijkstra_init(dijkstra);
dijkstra_update(dijkstra,source,0);
while(!dijkstra_empty())
while(!dijkstra_empty(dijkstra))
{
u32 cur = dijkstra_top();
dijkstra_pop();
u32 cur = dijkstra_top(dijkstra);
dijkstra_pop(dijkstra);
if(bitmap_test_bit(visited,cur))
continue;
@@ -905,7 +906,7 @@ static int find_optimal_path(
if(distance[next]<=distance[cur]+cij)
continue;
dijkstra_update(next,distance[cur]+cij);
dijkstra_update(dijkstra,next,distance[cur]+cij);
prev[next]=arc;
}
}
@@ -945,6 +946,7 @@ static void zero_flow(
* current iteration but I might be not too far from the truth.
* It comes to mind to use cycle cancelling. */
static int optimize_mcf(
struct dijkstra *dijkstra,
const struct linear_network *linear_network,
struct residual_network *residual_network,
const u32 source,
@@ -959,13 +961,13 @@ static int optimize_mcf(
zero_flow(linear_network,residual_network);
arc_t *prev = tal_arr(this_ctx,arc_t,linear_network->max_num_nodes);
s64 const*const distance = dijkstra_distance_data();
s64 const*const distance = dijkstra_distance_data(dijkstra);
s64 remaining_amount = amount;
while(remaining_amount>0)
{
int err = find_optimal_path(linear_network,residual_network,source,target,prev);
int err = find_optimal_path(dijkstra,linear_network,residual_network,source,target,prev);
if(err!=RENEPAY_ERR_OK)
{
// unexpected error
@@ -1358,6 +1360,7 @@ struct flow** minflow(
tal_t *this_ctx = tal(tmpctx,tal_t);
struct pay_parameters *params = tal(this_ctx,struct pay_parameters);
struct dijkstra *dijkstra;
params->gossmap = gossmap;
params->source = source;
@@ -1397,7 +1400,7 @@ struct flow** minflow(
struct residual_network *residual_network = tal(this_ctx,struct residual_network);
alloc_residual_netork(linear_network,residual_network);
dijkstra_malloc(this_ctx,gossmap_max_node_idx(params->gossmap));
dijkstra = dijkstra_new(this_ctx, gossmap_max_node_idx(params->gossmap));
const u32 target_idx = gossmap_node_idx(params->gossmap,target);
const u32 source_idx = gossmap_node_idx(params->gossmap,source);
@@ -1458,7 +1461,7 @@ struct flow** minflow(
combine_cost_function(linear_network,residual_network,mu);
optimize_mcf(linear_network,residual_network,
optimize_mcf(dijkstra,linear_network,residual_network,
source_idx,target_idx,pay_amount_sats);
struct flow **flow_paths;

View File

@@ -11,70 +11,70 @@
static void insertion_in_increasing_distance(const tal_t *ctx)
{
dijkstra_malloc(ctx,10);
struct dijkstra *dijkstra = dijkstra_new(ctx,10);
for(int i=0;i<dijkstra_maxsize();++i)
for(int i=0;i<dijkstra_maxsize(dijkstra);++i)
{
dijkstra_update(i,10+i);
assert(dijkstra_size()==(i+1));
dijkstra_update(dijkstra,i,10+i);
assert(dijkstra_size(dijkstra)==(i+1));
}
dijkstra_update(3,3);
assert(dijkstra_top()==3);
dijkstra_update(dijkstra,3,3);
assert(dijkstra_top(dijkstra)==3);
dijkstra_update(3,15);
assert(dijkstra_top()==0);
dijkstra_update(dijkstra,3,15);
assert(dijkstra_top(dijkstra)==0);
dijkstra_update(3,-1);
assert(dijkstra_top()==3);
dijkstra_update(dijkstra,3,-1);
assert(dijkstra_top(dijkstra)==3);
dijkstra_pop();
assert(dijkstra_size()==9);
assert(dijkstra_top()==0);
dijkstra_pop(dijkstra);
assert(dijkstra_size(dijkstra)==9);
assert(dijkstra_top(dijkstra)==0);
// Insert again
dijkstra_update(3,3+10);
dijkstra_update(dijkstra,3,3+10);
u32 top=0;
while(!dijkstra_empty())
while(!dijkstra_empty(dijkstra))
{
assert(top==dijkstra_top());
assert(top==dijkstra_top(dijkstra));
top++;
dijkstra_pop();
dijkstra_pop(dijkstra);
}
}
static void insertion_in_decreasing_distance(const tal_t *ctx)
{
dijkstra_malloc(ctx,10);
struct dijkstra *dijkstra = dijkstra_new(ctx,10);
for(int i=0;i<dijkstra_maxsize();++i)
for(int i=0;i<dijkstra_maxsize(dijkstra);++i)
{
dijkstra_update(i,10-i);
assert(dijkstra_size()==(i+1));
dijkstra_update(dijkstra,i,10-i);
assert(dijkstra_size(dijkstra)==(i+1));
}
dijkstra_update(3,-3);
assert(dijkstra_top()==3);
dijkstra_update(dijkstra,3,-3);
assert(dijkstra_top(dijkstra)==3);
dijkstra_update(3,15);
assert(dijkstra_top()==9);
dijkstra_update(dijkstra,3,15);
assert(dijkstra_top(dijkstra)==9);
dijkstra_update(3,-1);
assert(dijkstra_top()==3);
dijkstra_update(dijkstra,3,-1);
assert(dijkstra_top(dijkstra)==3);
dijkstra_pop();
assert(dijkstra_size()==9);
assert(dijkstra_top()==9);
dijkstra_pop(dijkstra);
assert(dijkstra_size(dijkstra)==9);
assert(dijkstra_top(dijkstra)==9);
// Insert again
dijkstra_update(3,10-3);
dijkstra_update(dijkstra,3,10-3);
u32 top=9;
while(!dijkstra_empty())
while(!dijkstra_empty(dijkstra))
{
assert(top==dijkstra_top());
assert(top==dijkstra_top(dijkstra));
top--;
dijkstra_pop();
dijkstra_pop(dijkstra);
}
}
@@ -82,14 +82,6 @@ int main(int argc, char *argv[])
{
common_setup(argv[0]);
insertion_in_increasing_distance(NULL);
insertion_in_decreasing_distance(tmpctx);
// test dijkstra_free
dijkstra_free();
// we can call it twice, no problem
dijkstra_free();
// does tal_free() cleansup correctly?
const tal_t *this_ctx = tal(NULL,tal_t);
insertion_in_increasing_distance(this_ctx);